Remove gdml requirement for Geant4
First commit with A2SIM for GEANT4.10p01. Various modifications in order to compile. At now works just in single core mode. Further implementation are under way for multi-core mode. In this release of GEANT4 many problems arise from the fact that GEANT4 has global variables as s (seconds) m (meters) and ROOT. Pointing these variables to the correct CLAS (CLHEP : Geant4 base its variables on the CLHEP ones) solved the problem