added tau Pt offset for relative isolation of HLT PFTaus (for Michal)
added default configuration for a new parameter
Merge pull request #4350 from jpavel/71x_tauIsoHLTOffset

Adding offset parameter to the tau isolation (for 71x)
Merge remote branch 'origin/CMSSW_7_1_X' into CMSSW_7_0_X