Update HSCP package for Run2

Following PR #5075

Changes done here are all contained in directory AnalysisDataFormats/SUSYBSMObjects and in SUSYBSMAnalysis/HSCP that are both used ONLY by the HSCP analysis group.
If you are not aware of these package, you can probably just approve these changes.

This is *NOT* affecting PAT at all, and none of this is run in production.

Thanks,
Loic