Extra changes for 2016, 2017 samples

Main changes:

• fix some bugs from !11 (merged) (and problems with scalefactor files)
• add L1 prefiring weight + systematics
• update list of systematics in plotIt
• add 2016, 2017 eras and luminosities in config
• update some branch names (e.g. b-tag SFs)
• use pileup weights computed by bamboo
• plot pt/eta/... of all jets instead of separate plot for leading/subleading/...
• tune job splitting
• for now, don't add theory systematics for "bugged" samples