Introduce GEANT4 Process(es) to the Truth

[alexbooth92]

Introduction of:

• start_process: physics process for the start of the trajectory as defined by GEANT4

and perhaps

• start_subprocess: physics subprocess for the start of the trajectory as defined by GEANT4
• end_process: physics process for the end of the trajectory as defined by GEANT4
• end_subprocess: physics subprocess for the end of the trajectory as defined by GEANT4

to the filled truth information.

ND_CAFMaker/src/reco/MLNDLArRecoBranchFiller.cxx

Line 307 in ac82792

// ValidateOrCopy(truePartPassthrough.creation_process, srTruePart.start_process)