- 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

      build all examples in one go
    - made necessary changes in package cmake files
      for this to work
    - updated documentation in Readme

Add root libs to (DY)LD_LIBRARY_PATH, make cmake find genmap. No longer need to have rootsys/bin in the path.

   - 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 ...