small bug fix for older compilers/os by Frank Gaede: pow(x,x) function is ambiguous with implicit conversion

    left shift count >= width of type 

   - updated versions and release notes

- howto with steps for preparing a new DD4hep release

--This line, and thowith steps se below, will be ignored--

A    doc/prepare_a_release.howto

   for release v00-08 and v00-09
   ( both have the wrong version number for the libraries 0.7 !)

Call notapple function for macs at the moment. Forgot to change this function during refactoring

    void setValue(unsigned lowWord, unsigned highWord )
 - added some simple unit tests for BitField64

Improved version of MC particle handler, fix calorimeter hit aggregation with multiple contributions

Add attr function for xercesc use, so that char arrays can be used to get xml elements (e.g., necessary to use ddsim w/ xercesc)

Include cmake module path for FindXerces
Forward the DD4HEP_USE_XERCESC variable and call DD4HEP_XML_SETUP
Forward DD4HEP_USE_BOOST and call find_package boost

Moved find_package to main cmakelists
use add_dd4hep_plugin to add library, create rootmap and install library
Moved xml_setup to main cmakelists

Moved find_package calls to main cmakelists
moved include_directories to main cmakelists
only use dd4hep_generate_rootmap

Split into apple and notapple functions, users just use dd4hep_generate_rootmap
removed commented code in generate_rootmap_apple

Move find_package xercesc to dd4hep_xml_setup, so all the xml treatment is in one place
Move find_package boost and lcio to main cmakelists, so they are done once and not repeated
Move include geant4_use_file to main cmakelists, so all of the geant4 treatment is in one place

Phi2 is the deltaPhi in Geant4, it is the EndPhi in TGeo

It is necessary to copy most of the cmake content, if the installation directory is not the same as the source directory
In that case the cmake folder would be missing.

Move option calls before checking deprecated _WITH_ variables, otherwise _USE_ variables are overwritten when not set in command line

 - increased version number to v00-07