Dev flavtag add os tunings

I added two compilable BDTs -- trained with XGBoost, but independent from the XGBoost libraries -- for the OSElectron and OSMuon tagger and updated their preselection cuts. I also added a new tuning "Summer2017Optimisation" which uses these new tagger configurations. This should already run when following the instructions given in the TupleProduction repo with the new tuning.