Add tofBin to stripDigiSimLink, associate recHit via simHit index

[wmtford]

This PR consolidates previous PRs 4520 and 4661. StripDigiSimLinks are modified to include the tofBin; strip digitizer builds simLinks with this additional information; TrackerHitAssociator uses direct simHit pointers for the strips. The performance blow-up observed with PR 4520 is fixed, and redundancy in the simHit maps is removed.

[cmsbuild]

A new Pull Request was created by @wmtford for CMSSW_7_2_X.

Add tofBin to stripDigiSimLink, associate recHit via simHit index

It involves the following packages:

SimDataFormats/TrackerDigiSimLink
SimTracker/SiStripDigitizer
SimTracker/TrackerHitAssociation

@cmsbuild, @civanch, @Degano, @mdhildreth, @nclopezo can you please review it and eventually sign? Thanks.
@GiacomoSguazzoni, @rovere, @VinInn, @cnuttens, @cerati, @threus, @venturia this is something you requested to watch as well.
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[cmsbuild]

+1
Tested at: 83e5da1
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-4678/362/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-4678/362/summary.html

[civanch]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_2_X IBs unless changes (tests are also fine).