72X - IIHE T2 submission script

This PR adds a script to submit multiple jobs locally to the IIHE T2. Documentation will be added to https://twiki.cern.ch/twiki/bin/viewauth/CMS/GhentTopSWGuide.
It also upgrades the branch to CMSSW_7_2_3, but the releevant commits are those on Dec. 10th/11th.