Add PU ID for btagging

[acaudron]

First implementation of a PU category in b-tagging validation code. Allow possibility to identify PU-jets based on gen-jets information. Option not yet switch on for RelVal production.

[cmsbuild]

A new Pull Request was created by @acaudron for CMSSW_7_1_X.

Add PU ID for btagging

It involves the following packages:

DQMOffline/RecoB
Validation/RecoB

@ojeda, @danduggan, @rovere, @cmsbuild, @nclopezo, @deguio, @Degano can you please review it and eventually sign? Thanks.
@ferencek this is something you requested to watch as well.
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@ktf you are the release manager for this.
You can merge this pull request by typing 'merge' in the first line of your comment.

[cmsbuild]

+1
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-2206/43/summary.html

[cmsbuild]

-1
When I ran the RelVals I found an error in the following worklfows:
50101.0 step2

runTheMatrix-results/50101.0_SingleMuPt10+SingleMuPt10FSIdINPUT+SingleMuPt10FS_ID/step2_SingleMuPt10+SingleMuPt10FSIdINPUT+SingleMuPt10FS_ID.log

you can see the results of the tests here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-2206/141/summary.html

[acaudron]

looking at:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-2206/141/runTheMatrix-results/50101.0_SingleMuPt10+SingleMuPt10FSIdINPUT+SingleMuPt10FS_ID/step2_SingleMuPt10+SingleMuPt10FSIdINPUT+SingleMuPt10FS_ID.log
The error looks to be due to missing input files which is unrelated to the proposed changes.

[cmsbuild]

+1
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-2206/144/summary.html

[deguio]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_1_X IBs unless changes (tests are also fine). @nclopezo, @ktf can you please take care of it?