to be used to only build detector envelopes
 - fixed visualization in teve_display to also
   show the envelope volume
 - visualize daughter level in dumpdetector (tabs)

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
    

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