Merge pull request #10 from gpetruc/heppy_7_2_2_patch2

thanks for these new features
remove fast objects
add __str__ to reco::GenParticle and remove legacy GenParticle/GenLepton
fix typo in autovars showing up when isMC = False
Add default configs and option to store individual bits for trigger studies
reusing Particle.__str__ seem not to work. better would be to have a free function baseP4Printing to be shared for different cases
Merge pull request #11 from arizzi/heppy_7_2_2_patch2

Thanks!
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)