modifications to Razor trigger modules for Run 2 HLT

* Modified HLT razor filter to allow consuming PF MET 
* HLT razor filter now inherits from HLT Filter class to allow saving online trigger quantities
* Helper razor hemisphere python config added
* More details on the razor triggers for Run 2 can be found at the latest TSG SUSY report https://indico.cern.ch/event/339419/contribution/6/material/slides/0.pdf and SUSY Trigger report https://indico.cern.ch/event/349250/contribution/2/material/slides/0.pdf
@vlimant 
What's this cff file for?
We only use cfi files generated by fillDescriptions within HLTrigger!