Fixes for building in 71X

I wanted to build this in CMSSW_7_1_X in order to run on the Stage1 Layer 2 emulator output. I believe all the changes I made are trivial EXCEPT commenting out this:
https://github.com/richard-cms/L1Ntuples/commit/bb4b1076c345df886c50310ff87914b279c9ed23#diff-63096b8c6aa4361cecbed9d75577b8c6L485
I wasn't sure what the proper way to update this for 71X (probably requires a migration to 'getByToken' instead of 'get'), please advise.

I also added a python cfi tailored to running on the Stage1 Layer2 output.