Integration of MVA/NoPU MET in central release

This PR contains the MVA and NoPU code the JetMET group wants to make available centrally, and eventually computed at the RECO and miniAOD level after discussion with the RECO/AT group.

This PR add the package RecoMET/METPUSubtraction, and add the pat configuration files needed for the MET uncertainty tool.
Several fixes and cleaning are also done on the patCaloMET configuration, the pileupjetid configuration, the pileupJetid training needed by the MVA and NoPU MET.

According to the JetMET devs,  there is a small bug in CMSSW which does not gives the good neutral energy fraction for jets with eta above 2.5. so it has been fixed by hand.
I discussed with some other JetMET people, I will fix that bug in the same PR.