added preliminary rho correction functionality
Merged topic_rho_corrections from repository matteosan1
bug fix in PhotonIso
bug fix in PhotonIso
bug fix in PhotonIso
a bug fix, rho corrections for PF iso and new PixelMatchFilter
Merge pull request #3114 from matteosan1/topic_rho_corrections

HLT -- A bug fix, added two PFIso producers, added rho corrections for PF Iso and a new PixelMatch Filter