Merge pull request #182 from ktf/move-to-next

Move CMSSW_7_3_THREADED_X to IB/CMSSW_7_3_X/next.
Automatically build a release when requested in the github issues
Merge pull request #183 from nclopezo/auto-build-releases

Automatically build a release when requested in the github issues
Switch production arch in CMSSW_7_3_0_pre1