ReleaseNotes.md

* 2017-10-13 Marko Petric ([PR#246](https://github.com/aidasoft/DD4hep/pull/246))
  ### DDCMS:
  - Improve the CMS excercise. New examples etc.
  - Support for simulation using DDG4 (at least partially - since not all subdetector volumes are accepted by Geant4).
  
  ### DDG4:
  - Event reader returns `EVENT_READER_EOF` if `EOF` is detected rather than a generic IO error.
  - Add generator status word to the `Geant4Particle` object. Remove the extension mechanism, which is very heavy to just add one integer.
  
  ### General:
   - We need to distinguish the plugins using some namespace mechanism. I started to introduce the namespace separator `"_".` Hence all DD4hep plugins start with `DD4hep_<plugin>`. I hope this does not break everything. If it does, please notify me and we can undo.

* 2017-10-13 Whitney Armstrong ([PR#243](https://github.com/aidasoft/DD4hep/pull/243))
  - Added helper function `getAttrOrDefault` (defined in  `DDCore/include/XML/Helper.h`) 
   This  function `getAttrOrDefault(xml::Element e, xml::XmlChar attr_name, T default_value)` will return the attribute  name,  converted to to type `T` but if it is not found it will return `default_value`. When building new detectors supplying this is useful for supplying default attribute values.

* 2017-10-19 Markus Frank ([PR#249](https://github.com/aidasoft/DD4hep/pull/249))
  * Improve the CMS tracker visualisation
  * Add DDG4 simulation example to DDCMS
  * Add some plugins to add visualisation attributes if required (not for the compact description)

* 2017-11-01 David Blyth ([PR#254](https://github.com/aidasoft/DD4hep/pull/254))
  - DDG4/python/DDG4.py: loadDDG4() changed to not raise exception if libraries are already loaded

* 2017-11-01 David Blyth ([PR#252](https://github.com/aidasoft/DD4hep/pull/252))
  - Added requirement of Python 2 in cmake/FindPYTHON.cmake.  This makes clear the requirement of Python 2, and resolves the issue where CMake tries to build with Python 3 in a system where both exist.

* 2017-11-07 Frank Gaede ([PR#256](https://github.com/aidasoft/DD4hep/pull/256))
  - bug fix in `BitField64::operator[std::string]() `
  - make uses of TString in DocumentHandler.cpp compatible with clang9 (on Mac)

# v01-03

* 2017-10-12 Frank Gaede ([PR#244](https://github.com/AIDASoft/DD4hep/pull/244))
  - allow for unbounded surfaces in DDRec
       - add new property `SurfaceType::Unbounded`
       - if a surface is marked unbounded `Surface::insideBounds()` ignores the volume boundaries (and only checks the distance to the surface)

* 2017-09-19 Whitney Armstrong ([PR#233](https://github.com/AIDASoft/DD4hep/pull/233))
  - Added helper  `CellIDPositionConverter::cellDimensions(const CellID& cell)`

* 2017-10-09 Frank Gaede ([PR#242](https://github.com/AIDASoft/DD4hep/pull/242))
  - improve `BitFieldCoder` class
      - remove heap allocation of BitFieldElements
      - add move constructors for efficient filling of vector

* 2017-09-29 Frank Gaede ([PR#238](https://github.com/AIDASoft/DD4hep/pull/238))
  - add new threadsafe class `BitFieldCoder` as replacement for `BitField64`
  - use as `const` everywhere
  - re-implement `BitField64` using `BitFieldCoder`
    - is thread safe if used locally 
    - can be instantiated from `const BitFieldCoder*`

* 2017-09-18 Markus Frank ([PR#234](https://github.com/AIDASoft/DD4hep/pull/234))
  - Created a new example showing the CMS tracking detector
    - Get CMS going with their evaluation. Added a package DDCMS with the conversion plugins for the silicon trackers and the corresponding conversion mechanism for their `xml` structure.

* 2017-09-18 Frank Gaede ([PR#232](https://github.com/AIDASoft/DD4hep/pull/232))
  - fix reading of stdhep/lcio generator files with generator statuses not in [0,3]
  - add `G4PARTICLE_GEN_BEAM` and `G4PARTICLE_GEN_OTHER` to DDG4
    -  `G4PARTICLE_GEN_BEAM`  is generally agreed to be used for beam particles (HepMC, LCIO)
    -  all other status codes vary from generator to generator and we use OTHER
  - for stdhep or lcio input the true generator status is preserved in the lcio output, regardless of its value
  - create a vertex for every parent-less particle in LCIOEventReader
    - this allows for example to read GuineaPig files ( non-prompt pair particles) or special user created files with non-prompt particles
   - Resolves #101

* 2017-09-20 Markus Frank ([PR#235](https://github.com/AIDASoft/DD4hep/pull/235))
  - A more complete version of the CMS tracker
     - Enhanced the CMS tracker example to be more complete.
     - Stopped at some point to convert all CMS algorithms. Hence, the tracker is not complete, but the remaining work looks to be purely mechanical.

* 2017-10-02 Frank Gaede ([PR#239](https://github.com/AIDASoft/DD4hep/pull/239))
  - add cell sizes to printout of `LayeredCalorimeterData::layer`
      - used in `dumpdetector -d`

* 2017-09-14 Frank Gaede ([PR#231](https://github.com/AIDASoft/DD4hep/pull/231))
  - adapt LCIOEventReader for Pythia8 and Whizard2
    - add all parent-less particles to outgoing vertex
    - fixes #226 and closes #229 
    - also used for stdhep files

* 2017-09-07 Daniel Jeans ([PR#227](https://github.com/AIDASoft/DD4hep/pull/227))
  - Fix calculation of cell position in `MegatileLayerGridXY`
  - previously, returned position was the lower corner of the cell
  - after this bug fix, it's the cell centre

* 2017-10-05 Frank Gaede ([PR#241](https://github.com/AIDASoft/DD4hep/pull/241))
  - remove deprecated and unused classes from DDRec

* 2017-10-05 Frank Gaede ([PR#240](https://github.com/AIDASoft/DD4hep/pull/240))
  - add `dd4hep::rec::FixedPadSizeTPCData.zMinReadout`
       - needed to describe the cathode thickness

* 2017-08-21 Markus Frank ([PR#221](https://github.com/AIDASoft/DD4hep/pull/221))
  - Document several classes in doxygen notation.
     - Aim is that there are (at least) no class headers without docs.
     - See [documentation](http://test-dd4hep.web.cern.ch/test-dd4hep/doxygen/html/annotated.html)

# v01-02                                                                                                                                                                        

* 2017-07-14 Daniel Jeans ([PR#204](https://github.com/AIDAsoft/DD4hep/pull/204))
  - add ncellsX/Y as a "parameter", allowing it to be set in compact description. This change is for easier use in the case of a MultiSegmentation. (Only a uniform segmentation can be defined in this way: for more complex cases, must set by driver.)                                                                                                                                                                                                                                 
  - change from array to std::vector to store ncells information                                                                                                                                                                             

* 2017-07-17 Markus Frank ([PR#206](https://github.com/AIDAsoft/DD4hep/pull/206))
  ## Implement ROOT persistency mechanism for detector descriptions (continuation of AIDASoft/DD4hep#202).
  Object extensions are now persistent.                                                                   
                                                                                                          
  This is however not for free: **it requires a dictionary for the extension itself and it requires a dictionary for the class holding the extension**. These are:
   - `dd4hep::DetElement::DetElementExtension<IFACE,CONCRETE>` for `DetElement` extensions.                                                                       
   - `dd4hep::SimpleExtension<IFACE,CONCRETE>` for simple extension managed by the user framework (user calls explicitly destructor).                             
   - `dd4hep::DeleteExtension<IFACE,CONCRETE>` for simple extension managed by dd4hep (dd4hep calls automatically destructor on hosting object destruction).      
   - `dd4hep::CopyDeleteExtension<IFACE,CONCRETE>`. As above, but these extensions support calling the copy constructor of the embedded object and hence allow to copy also the hosting objects.
                                                                                                                                                                                                
  Please note: to persistify these objects it was necessary to no longer use the type-info of the objects as an identifier, but rather a 64-bit-hash of the raw type-info-name. This relies that this name is identical across platforms. This typically is true for linux, but not enforced by any standard.                                                                                                                                                                             

* 2017-08-11 Andre Sailer ([PR#213](https://github.com/AIDAsoft/DD4hep/pull/213))
  - CMake:: dd4hep_generate_rootmap: use CMAKE_INSTALL_LIBDIR if it is set. If the macro is called from other libraries this variable might be set and should be used for consistency. Fixes #212

* 2017-07-13 Markus Frank ([PR#202](https://github.com/AIDAsoft/DD4hep/pull/202))
  ## Implement ROOT persistency mechanism for detector descriptions              
                                                                                 
  The following commits allow to save and restore Detector objects (ie. the full detector description) to/from ROOT. Most changes affected the usage of void pointers. 
                                                                                                                                                                       
  It is **NOT** possible to:                                                                                                                                           
   * save object extensions. Another usage of void pointers and type-info objects, which both cannot be saved.                                                         
   * save callback objects. Callbacks store in memory pointers to member functions. These depend on the loading of libraries at run-time and hence may differ from application to application.
   * save conditions slices. This shall be a futute extension. There should be no fundamental problem doing so - it was simply not yet done.                                                  
                                                                                                                                                                                              
  In the example area a new slot call "Persistency" was created with various tests:                                                                                                           
   * Save and restore simple conditions                                                                                                                                                       
   * Save and restore the MiniTel detector (`examples/ClientTests/compact/MiniTel.xml`)                                                                                                       
   * Save and restore the CLICSiD detector (`examples/CLICSiD/compact/compact.xml`)                                                                                                           
                                                                                                                                                                                              
  The detector examples also have a set of tests associated to check the validity of the restored information.                                                                                
                                                                                                                                                                                              
  ## Integrate `DDSegmentatation` into `DDCore`                                                                                                                                               
                                                                                                                                                                                              
  As a first step to start the cleanup of `DDSegmentation` the code was integrated into `DDCore`. For backwards compatibility a dummy library `libDDSegmentation.so` is kept, so that client cmake files directly referring `DDSegmentation` still work. **This tough is only a temporary measure and users should remove references to the DDSegmentation library.** Include files can be accessed as before. These are part of the `DDCore` include directory.                          

* 2017-08-15 Yorgos Voutsinas ([PR#216](https://github.com/AIDAsoft/DD4hep/pull/216))
  * Adding variable "nocore" for beam pipe (with default value = false) In case the variable appears in the BP xml file as "true", the BP sections will have no core of beam material, in order that someone might add various BP walls made of different materials while avoiding G4 overlaps. Example of use:                                                                                                                                                                           
  ```xml                                                                                                                                                                                                                                     
  <detector name="BeBeampipe" type="DD4hep_Beampipe_o1_v01" insideTrackingVolume="true" nocore="true" vis="BeamPipeVis">                                                                                                                     
  ```                                                                                                                                                                                                                                        

* 2017-08-15 Jan Strube ([PR#215](https://github.com/AIDAsoft/DD4hep/pull/215))
  - LCIOEventReader: adding parameter for the name of the MCParticle collection: `MCParticleCollectionName`

* 2017-08-14 Markus Frank ([PR#217](https://github.com/AIDAsoft/DD4hep/pull/217))
  ## Enhance ROOT Detector Description Persistency                               
  Conditions slices from the DD4hep conditions store can now be saved to ROOT files ans named objects. Conditions persistency examples are added to the `examples/Conditions` section.
  The examples are derived from the Telescope and CLICSiD example:                                                                                                                    
   - `Conditions_Telescope_root_save`                                                                                                                                                 
   - `Conditions_Telescope_root_load_iov`                                                                                                                                             
   - `Conditions_Telescope_root_load_pool`                                                                                                                                            
   - `Conditions_CLICSiD_root_save_LONGTEST`                                                                                                                                          
   - `Conditions_CLICSiD_root_load_iov_LONGTEST`                                                                                                                                      
   - `Conditions_CLICSiD_root_load_usr_LONGTEST`                                                                                                                                      
   - `Conditions_CLICSiD_root_load_cond_LONGTEST`                                                                                                                                     
                                                                                                                                                                                      
  ## Fix Handle Problem when Accessing Materials from Volumes                                                                                                                         
  A cast problem was not spotted in the last commit, which manifested itself in accessing invalid materials from volumes. This commit resolves #211 , reported by @jhrdinka.          
                                                                                                                                                                                      
  A set of tests checks this behaviour in the ClientTests: `ClientTests_volume_materials_<text>`, where the volume tree is scanned and for all sensitive volumes and access the corresponding `materials/TGeoMedium` entities from the volume object.                                                                                                                                                                                                                                     

* 2017-07-18 Shaojun Lu ([PR#208](https://github.com/AIDAsoft/DD4hep/pull/208))
  - added "#include <memory>" for the smart pointers to DD4hepRootPersistency.cpp

* 2017-07-19 Markus Frank ([PR#209](https://github.com/AIDAsoft/DD4hep/pull/209))
  - Implement `dd4hep::Tube` using `TGeoTubeSeg` (See also Issue AIDASoft/DD4hep#203 for details)

* 2017-07-21 Markus Frank ([PR#210](https://github.com/AIDAsoft/DD4hep/pull/210))
  ## Implement ROOT persistency mechanism for the conditions                     
                                                                                 
  Conditions pools can now be made persistent provided all the dictionaries for the payload objects are provided. A new class `ConditionsRootPersistency` allows to save and re-load conditions pools to/from a ROOT file. Such pools can either be:                                                                                                                                                                                                                                      
   - Simple `ConditionsPool` objects                                                                                                                                                                                                         
   - The entire `IOV` indexed pool set (class `ConditionsIOVPool`) or                                                                                                                                                                        
   - A the pool used by a `ConditionsSlice` (class `UserPool`).
   - A std::vector<Condition> which belong all to the same IOV

  In any case the restoration of the saved conditions is performed through the `ConditionsManager` interface in order to ensure proper management of the added condition objects.

  Some example plugin tasks were added in examples/Conditions:
   - `DD4hep_ConditionExample_save` to save conditions to a ROOT file.
   - `DD4hep_ConditionExample_load` to restore conditions from file.

  Others to come.

  ## Split of dictionary files
  The ROOT dictionary creation in `DDCore` was getting increasingly large. Now the ROOT dictionaries are created in several files, what firstly allows them to be produced in parallel and secondly eases the compilation due to smaller generated file sizes.


# v01-01

* 2017-07-06 Markus Frank ([PR#201](https://github.com/AIDASoft/DD4hep/pull/201))
  ## DDCore: Changes to the VolumeManager interface
  
    Recent descrepancies showed that the call to lookup a placement
    from the volume manager may have an ambiguous meaning:
    It may (as used until now) be the placement of thge closest
    detector element - a functionality used by various tests
    or be the placement of the sensitive volume itself.
    So far, since each sensitive volume in the DD4hep tests
    is represented by a DetElement structure, both
    approaches returned the same placed volume.
  
    Since there is the possibility to have sensitive volumes, which are not
    directly connected to a single DetElement structure, this call was
    split to resolve this ambiguity:
  
    /// Lookup a physical (placed) volume identified by its 64 bit hit ID
    PlacedVolume lookupVolumePlacement(VolumeID volume_id) const;
    /// Lookup a physical (placed) volume of the detector element
    /// containing a volume identified by its 64 bit hit ID
    PlacedVolume lookupDetElementPlacement(VolumeID volume_id) const;

* 2017-07-06 Andre Sailer ([PR#200](https://github.com/AIDASoft/DD4hep/pull/200))
  - Now will give a warning if multiple entities (e.g., constants) of the same name are defined in the XML

# v01-00-01

* 2017-07-04 Frank Gaede ([PR#199](https://github.com/AIDASoft/DD4hep/pull/199))
  - bug fix for VolumeManagerContext::toElement() and VolumeManagerContext::placement() 
        - set flag=true in VolumeManager_Populator::add_entry when 
           a ContextExtension is needed, i.e. sensitive volume is not DetElement's volume
  - fixes problems in CellIDPositionConverter

# v01-00

* 2017-06-22 Marko Petric ([PR#192](https://github.com/AIDASoft/DD4hep/pull/192))
  - Move `AlignDet_Telescope_readback_xml` to later in the pipeline since it depends on the output of `AlignDet_Telescope_write_xml`

* 2017-06-22 Andre Sailer ([PR#191](https://github.com/AIDASoft/DD4hep/pull/191))
  - Surface: fix memory leak of transformation matrix
  - XML::Layering: fix memory leak of contained layers in the object

* 2017-06-23 Andre Sailer ([PR#197](https://github.com/AIDASoft/DD4hep/pull/197))
  - Fix memory leaks for Tube, EllipticalTube and Polyhedron

* 2017-06-23 Andre Sailer ([PR#196](https://github.com/AIDASoft/DD4hep/pull/196))
  - CMake: add `Project( DD4hep )`, needed to get the correct CMAKE_CXX_COMPILER_ID on macs due to CMP0025 (cmake policy)
  - CMake: fix treatment of linker flags, they are now properly set for Linux and Macs to error when undefined functions are encountered at link time
  - CMake: fix elif --> elseif when checking threading libraries

* 2017-06-23 Frank Gaede ([PR#195](https://github.com/AIDASoft/DD4hep/pull/195))
  - fix crash in `dd4hep::rec::Surface` after changes in Handle assignment (PR #193)
  - fix use of deprecated `dd4hep::rec::MaterialManager` c'tor in Surface

* 2017-06-20 Frank Gaede ([PR#185](https://github.com/AIDASoft/DD4hep/pull/185))
  - bug fix in material utilities
       - call `MaterialManager( Volume v)` with `Detector.world().volume()`

* 2017-06-20 Marko Petric ([PR#184](https://github.com/AIDASoft/DD4hep/pull/184))
  - Reinstate the full test-suite on Travis

* 2017-06-20 Markus Frank ([PR#183](https://github.com/AIDASoft/DD4hep/pull/183))
  - Unify header guards in DDCore
  - Add header to steer ignoring warnings of rootcling generated dictionaries.

* 2017-06-20 Frank Gaede ([PR#182](https://github.com/AIDASoft/DD4hep/pull/182))
  - cleanup of namespace `dd4hep::rec`
    - remove obsolete bwd compatibility for `DD4hep::DDRec`
    - re-introduce `[deprecated]` warnings for unmaintained classes in DDRec/API 
    - re-fix deprecated c'tor for `MaterialManager` in material utilities

* 2017-06-20 Markus Frank ([PR#181](https://github.com/AIDASoft/DD4hep/pull/181))
  - Attack many warnings from:
    - `-Wshadow`
    - `-Winclude-hygiene`
    - `-Woverlength-strings` (int cling dictionaries)

* 2017-06-20 Markus Frank ([PR#179](https://github.com/AIDASoft/DD4hep/pull/179))
  - Remove a bunch of shadow warnings and include-hygiene warnings.

* 2017-06-21 Marko Petric ([PR#169](https://github.com/AIDASoft/DD4hep/pull/169))
  - Make boost explicit requirement for DD4hep and drop DD4HEP_USE_BOOST

* 2017-06-21 David Blyth ([PR#168](https://github.com/AIDASoft/DD4hep/pull/168))
  - Added environment helper scripts `thisdd4hep_only.(c)sh` that only set up variables for DD4hep and not for dependencies.

* 2017-06-19 Markus Frank ([PR#178](https://github.com/AIDASoft/DD4hep/pull/178))
  - Update documentation after reorganization of namespaces (put back previous docs).

* 2017-06-19 Markus Frank ([PR#175](https://github.com/AIDASoft/DD4hep/pull/175))
  ## DD4hep namespace reorganization
  
  Re-organize namespaces according to the decisions of the DD4hep developers meeting from 16th June we have decided:
  
  1. all namespaces will be lower case and shorter
      * rename namespace `DD4hep` -> `dd4hep`
      * rename namespace `DD4hep::DDRec` -> `dd4hep::rec`
      * rename namespace `DD4hep::Simulation` -> `dd4hep::sim`
      * rename namespace `XML` -> `xml` and `JSON` -> `json`
      * rename all other namespaces according to this pattern
  2. The namespace `DD4hep::Geometry::` will be incorporated into `dd4hep::`
  3. All utilities will be moved `dd4hep::detail`
  4. `LCDD` will be renamed to `Detector` and current `Detector.h` will be renamed to `DetElement.h`
  8. Examine if `DDSegmentation` can be incorporated into `DDCore` and make it volume aware
      * If this this cannot be achieved in whole place `DDSegmentation` into the right namespace
  
    ## DDParsers
  
    DDParsers are now a separate package. This does not make it yet standalone,
    but it is at the same level as e.g. DDSeqmentation. Any librarian is
    encouraged to externialize it fully.

# v00-24

* 2017-06-08 Markus Frank ([PR#160](https://github.com/AIDASoft/DD4hep/pull/160))
  * Add a new class `AlignmentsNominalMap`, which behaves like a `ConditionsMap` and handles alignment entries. 
  * The `AlignmentsNominalMap` is not a conditions cache per-se. This implementation  behaves like a `conditionsmap`, but it shall not return real conditions to the user, but rather return the default alignment objects (which at the basis are conditions as well) to the user. These alignments are taken from the `DetElement` in question `Alignment DetElement::nominal()`.
  
  * The basic idea is to enable users to write code "as if" there would be conditions present. This is important to ease in the lifetime of the experiment the step from the design phase (where obviously no conditions are taken into account) to a more mature phase, where alignment studies etc. actually are part of the "bread and butter work".
  
  * Added a corresponding example in examples/AlignDet:
  ```
  $>   geoPluginRun -volmgr -destroy -plugin DD4hep_AlignmentExample_nominal \
           -input file:${DD4hep_DIR}/examples/AlignDet/compact/Telescope.xml
  ```
     * Access the DetElement nominal conditions using the `AlignmentNominalMap`.
     Any use of DDCond is inhibited.
       1) We use the generic printer, which during the detector element scan accesses the conditions map.
       2) We use a delta scanner to extract the nominal deltas from the `DetElement`'s nominal alignments
       3) We use a `ConditionsTreeMap` to perform the alignments re-computation.

* 2017-06-08 Markus Frank ([PR#159](https://github.com/AIDASoft/DD4hep/pull/159))
  # Implementation of the decisions made at the Conditions mini-workshop
  
  ## Access mechanisms of DD4hep conditions for utilities
  
  Access to conditions is solely supported using the interface class DDCore/ConditionsMap.
  * All utilities must use this interface.
  * Any concrete implementation using conditions/alignment utilities must implement this interface
  * Basic implementation using STL `map`, `multimap` and `unordered_map` are provided.
  * A special no-op implementation of this interface shall be provided to access "default" alignment conditions. This implementation shall fall-back internally to the `DetElement::nominal()` alignment. 
  Known clients: `VolumeManager` (hence: DDG4, DDRec, etc.)
  
  Though this sounds like a trivial change, the consequences concern the entire conditions
  and alignment handling. This interface decouples entirely the core part of DD4hep
  from the conditions cache handling and the alignment handling.
  
  Based on this interface most utilities used to handle conditions, detectors scans
  to visit `DetElement` related condition sets, alignment and conditions printers etc.
  
  For details, please see:
  ```
  DDCore/include/DD4hep/AlignmentsPrinter.h
  DDCore/include/DD4hep/AlignmentsProcessor.h
  DDCore/include/DD4hep/ConditionsPrinter.h
  DDCore/include/DD4hep/ConditionsProcessor.h
  DDCore/include/DD4hep/DetectorProcessor.h
  ```
  
  ## Naming conventions for detector conditions
  
  * Condition are logically attached to DetElements
     * Condition names are: `DetElement.path()+"#"+condition-name`
         Example: `/world/LHCb/DownstreamRegion/Muon/M5/M5ASide/R3ASide/Cham046#alignment`
  
  * Condition keys are a `int64` compound of two `int32`:
  ```cpp
     union {
       int64 key;
       struct {
         int32 item_key;
         int32 det_key;     // Needs to be the high word to have a properly ordered map
       } values;
     };
     det_key  = hash32(DetElement.path())
     item_key = hash32(condition-name)
  ```
     **Condition keys must be unique throughout the detector description.**
  
  * Alignment conditions naming conventions:
    * Alignment-delta conditions are called `alignment_delta`.
    * Fully qualified alignment conditions are called `alignment`.
     DD4hep provided alignment utilities rely on this convention.
  
  * Other conditions can be named freely.
  
  ## Important Notice
  The **Alignment conditions naming conventions** are already used by several utilities involving alignments. If you plan to use these, do not freely ignore these recommendations. When the naming conventions are ignored, these utilities shall not work.
  
  ## Updates to DDCond
  DDCond implements a working conditions cache following the design criteria sketched above. The `conditionsSlice` object implements (though by forwarding to the `ConditionsUserPool`) a `ConditionsMap` interface.
  
  The `DD4hep_ConditionsMapUserPool` plugin implements in a very efficient way this interface using an ordered map. Using the above described key definition, this implementation allows very efficient scans of conditions/alignments etc. of individual detector elements, since conditions which belong to the same detector element are contiguous.
  
  ## Alignment handling/computations
  Using the conditions maps, the computation of (mis-)alignment data from deltas
  is no longer bound to the conditions mechanisms.
  
  A special utility called `AlignmentsCalculator` is put in place (see `DDCore/include/DD4hep/AlignmentsCalculator.h`) to facilitate the computation of a coherent set of alignments given a set of delta-parameters. This mechanism is much simpler, easier to understand and far less code intensive than the previously designed callback mechanism where alignments are obtained using conditions derivation.
  
  ## Update of the existing examples
  
  The example sets in DDDB, `examples/Conditions, examples/AlignDet`, `examples/DDDB` were updated according to the changed mechanism of accessing conditions. Here we can see the real benefits of the new approach: keeping same functionality, the examples became way off simpler. Simply count the number of lines of code.

* 2017-06-17 Marko Petric ([PR#170](https://github.com/AIDASoft/DD4hep/pull/170))
  - Add clang flag to warn about using namespace directive in global context in header

* 2017-06-17 Frank Gaede ([PR#167](https://github.com/AIDASoft/DD4hep/pull/167))
  - renamed the namespace DD4hep::DDRec to dd4hep::rec (see #166)
         - provide backward compatibility to outside world for now
  - moved the interfaces in namespace DDSurfaces to dd4hep::rec
         - provide backward compatibility to outside world for now

* 2017-06-15 Frank Gaede ([PR#165](https://github.com/AIDASoft/DD4hep/pull/165))
  - started to cleanup DDRec
        - don't use  LCDD::getInstance() in SurfaceManager and SurfaceHelper
        -  deprecate unused(?) classes in DDRec/API and DDRec/Extensions
        -  deprecate MaterialManager() using LCDD::getInstance()

# v00-23

* 2017-05-12 Marko Petric ([PR#152](https://github.com/aidasoft/DD4hep/pull/152))
  - Update CI to GCC 7.1 and LLVM 4.0 and include Geant4 10.3

* 2017-05-22 Frank Gaede ([PR#154](https://github.com/aidasoft/DD4hep/pull/154))
  - protect against NANs in Guineapig pairs files in Geant4EventReaderGuineaPig
  - make INFO printout more consistent  with dd4hep style

* 2017-06-07 Frank Gaede ([PR#157](https://github.com/aidasoft/DD4hep/pull/157))
  -  bug fix in test_cellid_position_converter
       - with this no tests for position from cellID lookup should fail
  - re-implement ```CellIDPositionConverter::cellID(pos)```

* 2017-06-08 Marko Petric ([PR#156](https://github.com/aidasoft/DD4hep/pull/156))
  - Mark all fallthroughs in case statements with attributes to suppress warning

* 2017-06-01 Frank Gaede ([PR#155](https://github.com/aidasoft/DD4hep/pull/155))
  - add new class rec::CellIDPositionConverter
        - replaces rec::IDDecoder
        - implement positionNominal(CellID id) and cellID(position)
       - prepare for using alignment map by separating transforms to DetElement and daughter volume
       - do not use deprecated methods/members in VolumeManager
  - add test_cellid_position_converter.cpp
  - add VolumeManagerContext::toElement
       - transform from sensitive volume to next DetElement

# v00-22

* 2017-04-28 Markus Frank ([PR#148](https://github.com/aidasoft/DD4hep/pull/148))
  Improvements to the compact xml processing
  ===========================================
  
  Elements may now be specified within compact in 2 ways:
  1) old way: create an effective element:
  `    <element Z="4" formula="Be" name="Be" >`
  `      <atom type="A" unit="g/mol" value="9.01218" />`
  `    </element>`
  
  2) create element by defining an isotope mixture:
  `    <isotope name="C12" Z="6" N="12"/>`
  `      <atom unit="g/mole" value="xxxx"/>`
  `    </isotope>`
  `.....`
  `   <element name="C">`
  `     <fraction n="0.9893" ref="C12"/>`
  `     <fraction n="0.0107" ref="C13"/>`
  `   </element>`
  
  Improved debugging of compact xml conversions
  The following tags allow to enable increased prinout depending on additional tags in the compact file:
  `    <debug>`
  `      <type name="isotopes"     value="1"/>`
  `      <type name="elements"     value="1"/>`
  `      <type name="materials"    value="0"/>`
  `      <type name="visattr"      value="0"/>`
  `      <type name="regions"      value="0"/>`
  `      <type name="readout"      value="0"/>`
  `      <type name="limits"       value="0"/>`
  `      <type name="segmentation" value="0"/>`
  `    </debug>`
  
  Disable the ROOT TGeo element table from the compact xml. 
  Note: ALL elements must then be specified in the XML material database.
  `    <geometry>`
  `      <clear name="elements"/>`
  `    </geometry>`
  
  By default compact accepts exactly one input file (others may be included therein).
  In order to process iteratively multiple input files, the opening and the closing of the
  geometry steering tags may be added to the compact description. This example 
  gives the default behaviour:
  `    <geometry open="true" close="true"/>`
  
  Please note: per compact file exactly ONE geometry tag is allowed.
  
  
  Debugging the DDG4 geometry conversion mechanism
  =============================================
  New boolean properties of the Geant4DetectorGeometryConstruction object,
  which result in debugging printouts (defaults are OFF):
    DebugMaterials
    DebugElements
    DebugShapes
    DebugVolumes
    DebugPlacements
    DebugRegions
    PrintPlacements
    PrintSensitives

* 2017-04-28 Ben Couturier ([PR#146](https://github.com/aidasoft/DD4hep/pull/146))
  * Trivial fix for the DDDB converter to create paramphysvol3D volumes, which are otherwise ignored.

* 2017-04-20 Andre Sailer ([PR#145](https://github.com/aidasoft/DD4hep/pull/145))
  - LCIOOutput: Add setting of ProducedBySecondary bit for SimTrackerHits if the hit is produced by a particle that is not stored in the MCParticle collection, needs lcio 2.8

* 2017-05-05 Andre Sailer ([PR#150](https://github.com/aidasoft/DD4hep/pull/150))
  - Always create dd4hepConfigVersion.cmake in CMAKE_INSTALL_PREFIX and cmake folder
  - Create DD4hepConfig.cmake also in cmake folder
  - renamed Cmake Macro GENERATE_PACKAGE_CONFIGURATION_FILES to DD4HEP_GENERATE_PACKAGE_CONFIGURATION_FILES so it does not clash with the macro of the same name in ilcutil/cmakemodules

* 2017-05-07 Andre Sailer ([PR#151](https://github.com/aidasoft/DD4hep/pull/151))
  - Use cmake to create Version.h file to contain dd4hep version information and macros
  - Change the way dd4hep package version is defined and set standard cmake variables for this purpose

# v00-21

* 2017-04-03 Marko Petric ([PR#142](https://github.com/AIDASoft/DD4hep/pull/142))
  - Update to the CI system:
    - Install directly cvmfs on base system, which removes the need for the parrot connector 
    - Replace CernVM docker with plain docker
    - This reduces the build run time from 50 min to 25 min

* 2017-03-27 Shaojun Lu ([PR#134](https://github.com/AIDASoft/DD4hep/pull/134))
  - Set verbose true for G4EmSaturation to printout Birks coefficient.

* 2017-03-29 Frank Gaede ([PR#139](https://github.com/AIDASoft/DD4hep/pull/139))
  - add a utility to dump the B-field for a given Volume
          - usage: dumpBfield compact.xml x y z dx dy dz [in cm]  
          - will dump the B-field in volume [-x:x,-y:y,-z,z] with steps [dx,dy,dz]

* 2017-03-29 Joschka Lingemann ([PR#138](https://github.com/AIDASoft/DD4hep/pull/138))
  - Direct implementation that calculates eta from cartesian coordinates
  - Fix: Add registration of Phi-Eta segmentation

* 2017-03-29 Joschka Lingemann ([PR#137](https://github.com/AIDASoft/DD4hep/pull/137))
  - Adding GridRPhiEta a segmentation of equidistant size in R, Phi and Pseudorapidity
  - Adding GridPhiEta a segmentation of equidistant size in Phi and Pseudorapidity

* 2017-03-28 Markus Frank ([PR#135](https://github.com/AIDASoft/DD4hep/pull/135))
  - Accidentally the Segmentations of Joschka were added in the wrong place of the hierarchy.
     I removed them. He will later add them to the proper location.
  - Some C++ warnings concerning the C++11 standard were also fixed.

* 2017-03-24 Yorgos Voutsinas ([PR#132](https://github.com/AIDASoft/DD4hep/pull/132))
  - modifying the LayeredCalorimeterData struct in order to cope with conical shaped calorimeters

* 2017-03-31 Markus Frank ([PR#143](https://github.com/AIDASoft/DD4hep/pull/143))
  - Add new test for multi segment multi collections segmentations using a calorimeter endcap.
     See also: https://github.com/AIDASoft/DD4hep/issues/141, which is still unresolved,
     but seems not to be directly related to the Monte-Carlo truth handling.
  - Side effect: add Geant4EventActions to dump hits and particles
  - Fix a linker problem for unicode tags.

* 2017-03-31 Frank Gaede ([PR#140](https://github.com/AIDASoft/DD4hep/pull/140))
  - clarify documentation for CartesianField and implementations
  - make clear that  void fieldComponents() has to add
     the new field to the given field vector

* Marko Petric 2017-03-23 
  - Convert Release notes to markdown
  - Add some text about WIP and issue tracking
  - Add CONTRIBUTING.md and PULL_REQUEST_TEMPLATE

* Markus Frank 2017-03-17
 
 - Add a new input type by parsing JSON files. The basic json interpreter
    is present and offers essentially the same interface as the XML persers.
    The integration to the compact dialect however is not yet done.
    It should become however a valid alternative to parsing XML files
    with a small maintenance overhead, since the enhancement implementation
    present in XMLDimesion.h, XMLDetector.h and XMLChildValue.h is shared
    and instantiated for both.

* Markus Frank 2017-03-10
 
 - New round to kill coverity deficiencies.
 - Add exception try-catch clauses around various main programs in UtilityApps
    See UtilityApps/src/main.h for details.

* Markus Frank 2017-03-09
 
 - Fix issue with long volume ids exceeding 32 bits.
    Test added in examples/ClientTests
 - Fix volume manager id identical placed volumes are used in different places of the hierarchy.
    Test added in examples/ClientTests
 - Remove various svn left-overs (ID$ strings etc.)


* Frank Gaede 2017-02-10
 
  - allow event readers to create more than one vertex per event
     this should be possible as most generator formats allow to specify
     more than one event vertex 
  - changed signature of Geant4EventReader::readParticles(int,Vertex*, Particles&)
        to Geant4EventReader::readParticles(int,Vertices&, Particles& )
  - implement in LCIOEventReader, Geant4EventReaderHepEvt and Geant4EventReaderHepMC
  - for now still one vertex only is created using the first final state particle
        for HepEvt and LCIO

# v00-20

* Frank Gaede 2017-01-13 
- fix computation of radiation and interaction lengths
- require the density to be specified in the materials xml file
 
* Frank Gaede 2017-01-04 
- adopt numbers in test_surface.cc to elements.xml
- use elements.xml generated with plugin in DDTest
-  add ROOT version to dumped element table

* Frank Gaede 2016-12-22 
- fix test_surfaces by adapting to elements.xml
- fix test_units by including elements.xml
 
* Markus Frank 2016-12-21 
- Add plugin to dump the default ROOT element table
 
* Markus Frank 2016-12-20 
- Remove obsolete build flags
 
* Markus Frank 2016-12-19 
- Add Multi-threading conditions example
 
* Andre Sailer 2016-12-16 
- Add drivers for Beampipe, Mask and Solenoid from lcgeo, changed name to dd4hep_*
 
* Rosa Simonielo, Frank Gaede 2016-12-15 
- add new struct rec::NeighbourSurfacesStruct defined for neighbouring surfaces
 
* Frank Gaede 2016-12-14 
- fix library pathes in env scripts for macos
- use DD4HEP_LIBRARY_PATH and full lib path on mac
- apply rpath compiler settings to GaudiPluginService
- make compatible w/ Geant4 10.3
 
* Marko Petric 2016-12-13 
- Fix compiler flag handling
 
* Daniel Jeans 2016-12-08 
- add utility graphicalMaterialScan
 
* Markus Frank 2016-12-07 
- Fix compiler error on MacOSX gcc 4.9
 
* Marko Petric 2016-12-07 
- Remove few tests from Travis
- move flag to CMAKE_SHARED_LINKER_FLAGS
- Remove the dynamic lookup on runtime for libs on mac
 
* Markus Frank 2016-12-05 
- First version of conditions and alignments
 
* Andre Sailer 2016-12-06 
- DDTest: fix location to install DDtest header files
- Remove minimum required cmake version from DD4hepBuild, this interferes with other packages depending on dd4hep
 
* Marko Petric 2016-12-02 
- Fix missing CLHEP in thisdd4hep.sh
- Clean up FindPYTHON.cmake file
- Change gaudi auto_ptr to unique_ptr since the auto is deprecated
- Fix initAClick
 
* Marko Petric 2016-11-29 
- Fix rpath issues on mac with python
- Add custom DynamicPath on mac when loading python libs
- Add function to set the DD4HEP_LIBRARY_PATH
 
* Marko Petric 2016-11-28 
- Update all minimum CMake versions
- Fix gitlab builds
- Rename MakeRootMap to MakeGaudiMap for consistency
- Remove ROOT5 things and make approprite fixed to the usage of ROOTConfig.cmake
 Remove FindROOT.cmake and use from now on ROOTConfig.cmake
 
 
* Markus Frank 2016-11-30 
- New version of conditions handling
 
* Andre Sailer 2016-11-25 
- Fix ProductionCut conversion in Geant4Converter.cpp: cut is a range
 
* Markus Frank 2016-11-24 
- Fix linker errors on MAC
- Remove compiler warnings on MACOSX
- First fixes to version of alignment constant processing also remove where visited the $ statements in the files.
They are useless, since git does not support them. Fixed some tests, which no longer properly worked in
the conditions area.
- First usable version of alignment constant processing
 
 
* Markus Frank 2016-11-16 
- Try to improve efficiency using C++11 default operations
 
* Markus Frank 2016-11-10 
- Simplify opaque data mappings for conditions
 
# v00-19
* 2016-11-17 D.Jeans
- rewritten MegatileLayerGrid class 
  - not backward compatible 

* M.Petric:
- improved Travis CI configuration 
- remove some tests from CI

# v00-18

* 2016-11-09 F.Gaede
- updated rec::LayeredCalorimeterData::Layer:
  - remove deprecated thickness 
  - add phi0  
- add copy assignement to rec::MaterialData

* 2016-11-08 M.Frank
- Improve conditions handling. Started to implement using simple telescope
  detector from C.Burr.
- Add variable DD4HEP_LIBRARY_PATH to be used on MacOSX El Capitane
  to overcome DYLD_LIBRARY_PATH protection issues.
- Fix to copy with negative(rebased) IDDDescriptor fields
  (affects IDDDescriptor and VolumeManager).
  2 New tests:
  - ClientTests/Bitfield_SidesTest.xml to test readout string:
    system:8,barrel:-2
  - ClientTests/Bitfield_SidesTest2.xml to test readout string:
    system:16,barrel:16:-5
    
* 2016-10-18 M.Frank
-  Due to pressure of the FCC folks, I tried to implement a more dd4hep like implementation of the
  the segmentation objects. For testing only CartesianGridXY. If this mechanism works,
  it could be a starting recipe for the rest of the segmentations. The draw-back of this approach is,
  that assignments are not reversible:
  dd4hep::CartesianGridXY xy = readout.segmentation();  // Works
  dd4hep::Segmentation seg = xy;                    // Should not work

-  Reason: the managed objects are different....at some point in time I will have to find a
  clean solution for this, but the required changes for such a solution shall be manageable.

# v00-17

* 2016-09-29 V.Volkl
  - Small fixes and extensions of DDEve. Show "Views" menu even if specifying xml on the command line.
    Add possibility to specify event data in EveDisplay method, rather than having to select it in the gui dialogue.
    Selects FCC EventHandler if specified in the config xml (as an "eventHandler"-attribute to the "display" node),
    but keeps default behavior if not.


* 2016-08-24 M.Frank
      - Adding first somehow useful implementation to use conditions and the consequent loading thereof.
	Used by the DDDB implementation/example. DDDB is an alternative way to populate the dd4hep
	detector description using LHCb's detector description database.
	The reason is, that only a running experiment has a reasonable base to conditions data
	to excercise the dd4hep conditions.
	If interested, please have a look in the DDDB examples.

  - Still TODO:
    - A formal way to bootstrap the conditions loading still has to be found.
    - Conditions loading from XML files and a small comprehensive example.

# v00-16
* 2016-07-26 Shaojun Lu  
- Added new MegatileLayerGridXY segmentation for Scintillator strip Ecal, which is implemented by K.Kotera, 
 and used by SEcal04Hybrid geometry driver.

 - many ( minor fixes ) by F. Gaede, M. Petric, A Sailer, ...

* 2016-06-24 M.Frank
- Implement multiple segmentations.
  Though one readout objects (associated to one DetElement) may only have on segmentation,
  The MultiSegmentation type allows to have several sub-segmentations, which can be chosen
  from.
  Please see examples/ClientTests/*/MultiSegmentations

- At the same time allow the readout object to defined multiple collections through
  the IDDescriptor.
  Please see examples/ClientTests/*/MultiCollections

- The combined example can be found in
  Please see examples/ClientTests/*/NestedSegmentations



* 2016-05-03 M.Frank
- Green light is ON. You may use revision 2237 and above.

* 2016-05-03 M.Frank
- **Mega commit. Do not use until green signal arrives with seperate release notice.**
- Package DDDB: Prove of concept, that we can populate the geometry also from other
  sources than xml files obeying the lccdd notation.
- DDCore/XML: Implement the possibility to use external entity resolution for Xerces.
  There is not equivalent in TinyXML (AFAIK).
- Remove some of the Spirit parsers, since the libraries are getting way too big.
  This implicitly assumes, that object properties of 'exotic' types such as
  deque<long double> etc. are not really used. If you need properties stay to the obvious:
  string, int float, double and vectors, maps and sets thereof!
- DDG4 needed to public the DDG4Python include directory (Now in DDG4/Python).
  Reason: try to create ROOT 6 dictionaries, which can be relocated for release purposes.
- ROOT 6 dictionary generation: Create dictionaries with the additional flag:
  "-inlineInputHeader" which physically includes the header files used to generate the 
  dictionaries --> relocatability.

* 2016-03-21 M.Frank
- Add additional vertex argument to EventReader::readParticles, which supposedly should

* 2016-03-03 M.Frank
- Improve/complete job options type palette. 
- Allow modify the Geant4IsotropGenerator to shoot particle distributions according
  to several distributions:
  flat in : uniform, cos(theta), eta/pseudorapidity, ffbar (1+cos^2 theta)
  Option: generator.Distribution = 'cos(theta)'
  Default is uniform.

# v00-15     
* 2016-02-15 A.Sailer
-  LCIOStdHepReader.cpp
   - fixed memory leak, compiled and valgrinded

* 2016-02-10 F.Gaede
- added utility  dd4hep::xml::setDetectorTypeFlag()
  to set the TypeFlag from xml element <type_flag type="0x42"/>
- select detectors with 
  dd4hep::DetectorSelector(description).detectors(  ( dd4hep::DetType::TRACKER | dd4hep::DetType::ENDCAP )) ;
- used in UtilityApps/dumpdetector.cc
- added detector_types.xml with int constants defined in DetType.h, include with :
  `<include ref="${DD4hepINSTALL}/DDDetectors/compact/detector_types.xml"/>`
  - add elements to xml, e.g.
    <type_flags type="DetType_TRACKER +  DetType_ENDCAP  + DetType_PIXEL + DetType_STRIP "/>

* 2016-02-10 M.Frank
- DDCond:
    First implementation of conditions access. Required some movements of files
    from DDG4 (Properties) and some changes in the core conditions implementation.
    The basic infrastructure is now present. Don't know yet however how buggy it is...

* 2016-02-05 F.Gaede
-  added DetElement::typeFlag() and DetElement::setTypeFlag(unsigned int types)
- added utility class DetType for setting detector type properties in type flag

* 2016-02-03 N.Nikiforou
- DDDetectors
  - Added plugin dd4hep_GenericSurfaceInstallerPlugin, copied from lcgeo
    to allow installation of surfaces to any sliced detector
  cmake/Doxyfile.in
  - Added DDDetectors to the sources directory so Doxygen picks up the
    plugin documentation

* 2016-02-02 F.Gaede
- set momentum at endpoint (if lcio version > 2.6 ) for MCParticles in Geant4Output2LCIO.cpp 
- fixed printlevel in Geant4Action::print()
- removed random lines drawn in teveDisplay
- dont't print DetectorData by default in dumpdetector

* 2016-02-02 A.Sailer
- DDG4
  - Implemented SimulatorFlags (DDFORHEP-17)
    * In ParticleHandler: vertexIsNotEndpointOfParent, Stopped, leftDetector
    * Steerable distance for vertexIsNotEndpointOfParent
    * TCUserParticleHanlder Simulator flags: DecayedInTracker, DecayedInCalorimeter

* 2016-01-21 A.Sailer/M.Frank
- DDG4
  - Improved user defined physics constructors
    * Allows user defined global rangecut
    * Allows extending particle table (e.g. B-Hadrons unknown to geant4)

* 2016-01-18 F.Gaede
- fixed default c'tors in DDRec/DetectorData.h  to zero initialize sub-structures (LayerLayout etc)

* 2016-01-13 F.Gaede
- allow the default sensitive action to be a tuple with parameter dictionary in DDG4.py/ddsim.steer e.g.:
  SIM.action.tracker = ("Geant4TrackerWeightedAction", {"HitPositionCombination" : 1 , "CollectSingleDeposits" :  False } )
- fixed endpoint in MC-truth particles
 
* 2016-01-11 F.Gaede
- fix hit momentum in Geant4TrackerAction (Geant4SDActions.cpp)

* 2016-01-11 A.Sailer
- DDG4
  - Add LargestAcceptableStep to field setup

* 2016-01-07 A.Sailer
- DDG4
  - Fix the logic for skipping of events at the start of input files: LCIO, HepMC, stdhep and HepEvt
  - Event number in lcio outputfile takes skipped events into account now

* 2016-01-06 F.Gaede
- bug fix in DDSurfaces::ISurface for surface properties (orthogonal/parallel to z)
  (affected ILD VXD)

* 2016-01-05 F.Gaede
- added print functions for rec::DetectorData objects
- used in dumpdetector:
  dumpdetector compact.xml -d 


* 2015-12-09 N.Nikiforou
- UtilityApps/teveDisplay
  - Modified teveDisplay to have three separate collections of surface vectors (u,v,n) 
    instead of one collection. Now the vectors are colored differently.
  - Changed signature of getSurfaceVectors() to allow selection of o,u,v,n vectors to 
    add to the collection, added option for name and color of collection.
  - Renamed surface list collections to "HelperSurfaces" and "SensitiveSurfaces".
  - Changed signature of getSurfaces() to allow setting of name and color of collection.
  

* 2015-12-01 M.Frank
- DDG4
  - Remove some of the compilation warnings
  - Remove energy cut in sensitive detectors
    If you though need, use a Geant4Filter to mask the action processing
  examples/CLICSiD
  - Add a few tests for materialscan and simulation setups using XML or CINT.
  examples/ClientTests
  - Add a few tests for materialscan and simulation

* 2015-11-24 M.Frank
- DDG4
  - Implementation of multi-threading mode.
    To use and understand, please consult the DDG4 manual from the doc area.
  - "Old" Single threaded mode and functionality is preserved.
  - Numerous new classes supporting thread and master specific setup
    functionality.
  - Support for python configuration (see manual for details)
  - Support for global Geant4Actions executing in thread reentrant shared mode.
    (see manual for details)
  - DDG4 examples: DDG4/examples/CLICSidSimu.py deleted and replaced with:
    1) DDG4/examples/SiDSim.py  (single threaded, old example)
    2) DDG4/examples/SiDSim_MT.py (multi threaded version of SiDSim.py)

 -DDCore:
  - Support user formats for the default printout statements for nicer printouts.
  - Removal of compiler warnings

* 2015-11-23 F.Gaede
- added glbal method dd4hep::versionString() 

* 2015-11-13 S.Lu
-  Added a new AHcal Barrel segementation: TiledLayerGridXY, to be used e.g.  
   for the ILD AHcal Barrel Sensitive layer segmentation design.

* 2015-10-30 F.Gaede
- fixed LCIOFileReader to use sequential reading mode
  as using direct access always required runNum==0 and sequential evt nums ...
   

* 2015-10-15 F.Gaede
- DDSurfaces::ISurface/Surface
  - added implemation of conical surfaces 
    - ICone, VolConeImpl, VolCone, ConeSurface

* 2015-10-13 M.Frank
- DDG4
  - Remove explicit constructors for modular physics lists.
    Use the native Geant4 provided G4PhysListFactory instead.
    The physics list is instantiated as before with the "Extends" property.
  - Implement angular ranges in the Geant4IsotropeGenerator for phi [0,2pi] and theta[0,pi]
  - New sensitive detector Geant4TrackerWeightedAction
    Attempt to properly process combined deposits in tracking detectors.
  - Debug component Geant4SurfaceTest similar to the standalone program
    test_surfaces, but to be appended as a DDG4 event action for event by event
    tests of hits.

* 2015-10-09 M.Frank
- DDG4
  - Extend the functionality of the DDG4 plugins
    Geant4InteractionVertexBoost and Geant4InteractionVertexSmear.
    If the Mask property is set to -1, all interactions present
    at call time are smeared/boosted according to the parameters.
    Note, that the position of the plugins within the generation 
    sequence is important.
  - Add a new generator Geant4GeneratorWrapper to allow the use
    of native G4 generator classes such as the G4ParticleGun or
    the G4GeneralParticleSource. Still to be tested.
  - Extend the Geant4Random functionality: May now be instantiated
    like any other Geant4Action. Users may set the seed or the 
    luxury level.
    All calls to HepRandom (CLHEP) or gRandom (ROOT) will re-use 
    this instance. See DDG4/examples/CLICRandom.py for illustration.
  - Updated DDG4 manual.

* 2015-09-30 F.Gaede
- updated createGearForILD.cpp to use new parameters in LayeredCalorimeterData
  ( innerThickness, innerRadLength, etc)


* 2015-09-15 F.Gaede
- refactoring of Surface classes:
    - made VolSurface a reference counting handle to 
      a polymorphic pointer of type VolSurfaceBase
      - this should facilitate the creation
        of dedicated surface classes for special cases
        such as inside the beampipe or the face of the calorimeter

* 2015-08-27 F.Gaede