cleaned code, reduced verbosity, map with mva variables built, returning vertex with max_mva_id
cleaned code, reduced verbosity, map with mva variables built, returning vertex with max_mva_id
a function is added which makes pho-p4 correction according to correct
vertex choise.
Code cleaning
Merge pull request #41 from camilocarrillo/master

MVA Vertex ID update for flashgg alpha
Merge pull request #42 from OlivierBondu/PhotonCorrection

Photon 4-momentum correction