No code changes. Common code formatting removing tabs, replacing with spaces (tab-size=-2) + emacs reformatting.

    object to instantiate a G4VSensitiveDetector 
    class
    ->  allows to use pre-existing SD classes 
    -> changed macro DECLARE_SENSITIVEDETECTOR to
       create a factory, thus replace:
       //    typedef Geant4GenericSD<TrackerCombine>  Geant4TrackerCombine;
       typedef SimpleG4SDFactory< Geant4GenericSD<TrackerCombine> >  Geant4TrackerCombine;

 - changed to use standard way of finding geant4 with CMake:
   -D Geant4_DIR=_path_to_Geant4Config.cmake 
   (this script provies also the dependencies used to build geant4)

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