- Reload the current generator
  - Load a different one
  - Adding corresponding button in the GUI

 - Delete the actual geometry
 - Clear the Detector Manager
 - Reload Geometry file

For this to work a couple of thing has been done:
 - InitializeRootInput now need an extra SetBranchAddress to tell the
   tree that the previous address is no longer in use
 - Scorer can not be cleared, so need to be retrieved in case of a
   reloading. If they do not exist they are created
 - This is done using the new CheckScorer static method from VDetector

* editing the NPSimulation UI for nicer interface
 - adding menue and icon for common command
 - adding free icons for nice interface

* Adding creation of small sample cube by the material manager to ensure
* every declared material are used, so no crash when writting the DEDX
* tables

* Advancing Tiara Barrel Simulation, now working (still to be tested
extensively)

 - all material were always define but not use, causing crash in DEDX
   table output
- code clean up for Plastic.cc

* changing vis.mac file to use OGLI instead of OGLIQt interface

* adding Dictionnary for VDetector class to avoid error message in root

* The proton were registered as ion and did not interect any mor

* project

* outputted incorrectly

* committed prototype

  it was giving linking errors in NPAnalysis
  + the main changes have been to declare the AddHisto1D and AddHisto2D
    methods in 'public' instead of 'private' in VSpectra.h
  + some cleaning for including headers in NPLib/T*Spectra.{h,cxx}

* introductiong VSpectra a template virtual class from which derived the
* TSpectra classes