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.

I would suggest you to use Log Message Service and avoid cout (except for purely test purposes like in test/ directories).
After all it is there for that purpose (providing more functionality for a large software like CMSSW ). Generally you can not use cout but you hide it behind a flag. I won't comment on cout in use below.