Convert DTDigitizer to stream module

[Dr15Jones]

Made DTDigitizer thread safe by replacing std::cout with LogPrint.
Once this was done DTDigitizer was converted to a stream module.
In addition, fixed a once pre-job memory leak.

[cmsbuild]

A new Pull Request was created by @Dr15Jones (Chris Jones) for CMSSW_7_3_X.

Convert DTDigitizer to stream module

It involves the following packages:

SimMuon/DTDigitizer

@cmsbuild, @civanch, @nclopezo, @mdhildreth can you please review it and eventually sign? Thanks.
You can sign-off by replying to this message having '+1' in the first line of your reply.
You can reject by replying to this message having '-1' in the first line of your reply.
@nclopezo, @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
Tested at: 06baa94
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-6081/479/summary.html

[civanch]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_3_X IBs unless changes (tests are also fine). This pull request will be automatically merged.