Hlt validation 2

This is the new validation code for the BTag at HLT.

It is a completely new code (HLTriggerOffline/Btag), plus a small change of HLTrigger/Configuration/python/HLTrigger_EventContent_cff.py in order to keep in HLTDEBUG the btag variables used for the validation. 

The code was developed in CMSSW_7_2_0_pre4.