Add RelVals for Exo HLT and Tk

Add HSCP stops, fractionally charged particles, and WpE for relvals. For Exotica HLT validation and for Tk POG RECO validation of dE/dx.
You should be aware that as far as I know generator/pdtFile has no effect for either Pythia6 or Pythia8 (but all of the needed information should anyways be passed through the slha file...)