Add PFCluster Isolation to miniAOD electrons and photons (as #8221 , redone in 740pre9)

[slava77]

(copy-paste from #8221)

As the title says this PR add to floats to electron and photon to store PFCluster Isolation as computed at the HLT.
It contains:

• Factorized isolation computation algorithm so that it can be run by the HLT and offline producers (RecoEgamma/EgammaIsolationAlgos). I have checked that HLT results stays the same.
• Modified Electron.h and Photon.h DF to add the two numbers. (DataFormats/PatCandidates)
• Updated PAT and MiniAOD configurations to store the value in the object. (PhysicsTools/PatAlgos)

The idea is to compute at RECO level the valuemap with the isolation values and propagate it to the miniAOD.
Right now the filling is not activated since we are missing the ValueMap into RECO relvals so it wouldn't pass the standard tests. I have privately checked the filling is ok.

[slava77]

@cmsbuild
please test

[cmsbuild]

A new Pull Request was created by @slava77 (Slava Krutelyov) for CMSSW_7_4_X.

Add PFCluster Isolation to miniAOD electrons and photons (as #8221 , redone in 740pre9)

It involves the following packages:

DataFormats/PatCandidates
PhysicsTools/PatAlgos
RecoEgamma/Configuration
RecoEgamma/EgammaHLTProducers
RecoEgamma/EgammaIsolationAlgos
RecoEgamma/EgammaPhotonProducers

@perrotta, @cmsbuild, @nclopezo, @cvuosalo, @fwyzard, @monttj, @Martin-Grunewald, @slava77, @vadler can you please review it and eventually sign? Thanks.
@rappoccio, @Sam-Harper, @imarches, @ahinzmann, @acaudron, @mmarionncern, @lgray, @jdolen, @nhanvtran, @schoef, @ferencek, @mariadalfonso, @pvmulder, @TaiSakuma this is something you requested to watch as well.
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[slava77]

+1

for #8501 8f79371
this is the same code as signed off for #8221 29780dd
which diverged too much and needed a rebase

[Martin-Grunewald]

+1