+ In NPA, use directly input files from input ROOT file to be analysed 
     if not no input file is given.
   + TAsciiFiles from first input ROOT file in the TChain is taken.

   + when input files are not found, does not exist sytematically
   + it is done manually in Simulation.cc

   + TAsciiFile classes containing input files are now files here and not
     in Simulation.cc anymore

   + search for input files in the $NPTOOL/Inputs/* and local directories
     is now performed in this class
   + this search was done previously in DetectorConstruction.cc and
     PrimaryGeneratorAction.cc files. these files have been modified
     accordingly.
   + If input files are not found, program exits

 - User can no desable all branch except the one concerning the NPA detector in order to improve execution speed

 - A singleton class to make more easy to use NPTool Prog.
 - Class is implemented and tested on one Ananlysis Project