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

    - DDExamples no longer built with DD4hep
      => will become standalone packages
    - moved UtilityApps from DDExamples to root level
      apps are built by default
    - create DD4hepConfig.cmake
    

Remove materials from LCDD. Look them directly up in the TGeoManager instance and avoid double caching.

  - added Property $Id$ to all *.h *.cpp and *.xml files
    to allow versioning with SVN

Have a common representation for all unicode macros. Fix UtilityApps to print message if plugins are not found.