Changed Selection class to incluse GetSelectedPFJets methods.  These methods are clones of the GetSelectedJets methods but return a vector of TRootPFJets instead of TRootJets.  This makes accesing PF information possible and since there is little reason to use non-PF jets from here out, this should become the standsrd jet selector.

Also added in Tools/src/JetCombiner.cc and Tools/interface/JetCombiner.h for use with MVAComputer and MVATrainer.  Whether or not these are compatablie with the currently used TMVA is yet to be established.