- optional token, keeping retrocompatibility
 - allow to use "beam" at rest as source for gamma cascade

* Fixing minor bug in NPBeam and NPReaction

 - In the case of multiinteraction in the same volume, the scorer was keeping only the last energy deposit, instead of summing them
 - The threshold has been move in the Read sensitive and is no longer in the scorer, as the energy deposit can be down in multiple step each of them below threshold and be ignored if the threshold is applyed individually.

 - NPS was giving conflict between NP system of Unit and CLHEP one, this is was fixed by a nested ifdef on HEP_SYSTEM_OF_UNIT

* Fixing issue with S1:
 - in Detector Manager a tipo was desabling the condition compilation of S1

* Fixing issue in Isotropic:
 - conflict when the particle was light nuclei given by its name (eg proton instead of 1H)
 - Problem is fixed and user can use gamma, proton, deuton, triton and alpha spelling

   + this allows to remove CLHEP dependency in NPLib
   + this allows to remove Constant.h file

 - Try as an absolute or relative path
 - if fail try in the standard location
 - if fail exit with error code 1

 - Renaming of private member of Initial Condition
 - Beam energy was not set in Read Configuration

 - fixing couple of bug
 - remove some warning
 - enhance performance

 - Only one read configuration file method
 - lighter code
 - possibility to use TH1F for cross section shoot

 - Add associate class in NPL
 - Add Function in NPL

Some code clean up has been done as well (cosmetic change for the most)