Add LheD_tracker simulation to CTests, add batch parameter to LheD_tracker.py, fix a typo in the script and Readme (File name capitalization)

Loop over the xml files and just run converter with different types, based on the tests from examples/SimpleDetector

Hopefully I got the assemblies right now. Assembly test added in examples/ClientTests. Please see also doc/release.notes

- DDSegmenation now comes with its own factory and with generic access to segmentation parameters
- Removes the necessity of implementing different XML parsers in DDCore
- DD4hep::Segmentation becomes a lot simpler and its Object is now following a standard decorator pattern, completely removing any need of messing with the vtable
- compact2lcdd works for example with BarrelCalorimeter from CLICSiD example (other examples need to adapt their XML to valid segmentation names)
- See also examples/Segmentation/SegmentationTest for stand alone example
- The segmentation names and their parameter names do NOT follow current SLIC conventions. Once SLIC depends on DDSegmentation this will work transparently.

   -> already in $DD4HEP_LIBRARIES

Added calorimeter reco interface using extensions

   - use version suggested by A.Sailer for all but macos (APPLE)
   - added extra function dd4hep_generate_rootmap_apple()
     this version sources the thisXXX.sh scripts
     before running genmap - but does not seem to work for Linux
     -> needs to be resolved ...

    - ./bin/thisdd4hep.sh now initializes also ROOT
      and optionally geant4
    - cmake/thisdd4hep_package.sh.in is used in 
      examples to create thisILDExDet.sh and thisILDExSimu.sh
  
  - the thisdd4hep.sh script is now also used in the build process
    for generating the rootmap files

    - is now  build standalone
    - needs proper setting of (DY)LD_LIBRARY_PATH