Clean up, moved skim config files into new directory 'skimfiles'

- Adapted onlyPAT.py, openHLT.py, openHLT2PAT.py to read skim config files from a subdirectory
- Removed 7XY files temporarily

	deleted:    hlt_7XY.py
	deleted:    setup_7XY_cff.py
	deleted:    hlt_MET_dev.py
	modified:   README.md
	modified:   onlyPAT.py
	modified:   openHLT.py
	modified:   openHLT2PAT.py
	new file:   skimfiles/__init__.py
	renamed:    skimHLTL1ETM40_cfi.py -> skimfiles/skimHLTL1ETM40_cfi.py
	renamed:    skimHLTMET80_cfi.py -> skimfiles/skimHLTMET80_cfi.py
	renamed:    skimHLTPFMET150_cfi.py -> skimfiles/skimHLTPFMET150_cfi.py
	renamed:    skimHLTPFMETplusX_HTMHT_cfi.py -> skimfiles/skimHLTPFMETplusX_HTMHT_cfi.py
	renamed:    skimHLTPFMETplusX_cfi.py -> skimfiles/skimHLTPFMETplusX_cfi.py
	renamed:    skimHLTPFNoPUHT350_cfi.py -> skimfiles/skimHLTPFNoPUHT350_cfi.py
	renamed:    skimHLTSingleMu_cfi.py -> skimfiles/skimHLTSingleMu_cfi.py
	renamed:    skimL1ETM36ORETM40_cfi.py -> skimfiles/skimL1ETM36ORETM40_cfi.py
Fetched updates from official, and merged them into master

- Disabled loading of setup_cff.py
- Can clone a path with a new prescale with a unique name