Removed unneeded const_cast from TrackAssociatorByHits

Removed unneeded const_casts and avoided copying std::vectors. The
const_casts had been spotted by the static analyzer.
Add ability to account for additional CPU time per event

Created a new base class for the Timing Service so other modules can report additional CPU time spent by a job external to cmsRun.
Merge pull request #4173 from Dr15Jones/removeUnneededConstCastTrackAssociatorByHits

Removed unneeded const_cast from TrackAssociatorByHits
Merge pull request #4213 from Dr15Jones/createdTimingServiceBase

Add ability to account for additional CPU time per event.
Merge remote branch 'origin/CMSSW_7_2_X' into CMSSW_7_0_X