Adding cross section only on MC, and default to 1
replace 'from ROOT.reco import GenParticle' with 'GenParticle = ROOT.reco.GenParticle'
HeppyCore: time report functionality for heppy (run with -t or --timereport to enable)
Merge pull request #12 from gpetruc/heppy_7_2_2_patch2

Thanks Giovanni.