print yields with err
drop obsolete DiLepPair enum
get rid of SusyAnaDefsMatt

Details:
- drop the remaining unused enums
- define LeptonType inside MeasureFakeRate2
- within MeasureFakeRate2, define a vector or lepton types,
  and use that to loop when booking and filling the histograms
- buildWeightedMatrix.py now is probably broken (was parsing
  SignalRegions from SusyAnaDefsMatt); will fix once the cleanup
  is complete
avoid 'using namespace std' in headers; include std::string where needed
drop unnecessary includes