Adding a GRSISpoon Fragment Tree

- Adapted GrsiSpoon classes TTigFragment and TFragment to be used in the simulations
- updated the MakeFile in the dataRootClasses directory
- updated the CMakeLists.cxx
- Addings in the RootManager.cxx
- updating the README file in the dataRootClasses directory
- created the auxilliary file (linkdef) for the new class.
- The creation of the tree now is in RootManager::SetTree(), called in the constructor.

NB - The implementation is not 100% complete, still need to have the mnemonics (related to the regions implementation etc..). However quantities like energies or time could be assigned and stored in the fragment tree right away.

NB - I have commented the detector classes in the RootManager::SetTree() to test the new TFragment class. If you want to use them, uncomment and compile.

NB - Next steps for any one who want to help  : 
                    - implement and use the mnemonic as the key
                    - store the mnemonic in the Fragment Tree
                    - produce a tree and analyze it as if it's a real data tree.