Trigger workflow

Some trigger work in progress (issue #85).
So far:
- [x] added the module to store the trigger objects of interest (off by default)
- [x] removed '2012' from unfolding selection naming as its applied to both 7 and 8 TeV samples
- [x] added the flag for modified (tag and probe) selection to drop dilepton veto
- [x] add the Z mass window cut for 2 leptons
- [x] increase the list of trigger objects of interest, map to corresponding run numbers and HLT paths
- [x] adjust the jet cleaning so that the jet collection is cleaned against all signal electrons