working on nice event display
working on pf candidates display
checkpoint event display debugging
working on cluster-cluster linking in HGC
checkpoint
checkpoint
fixed issue with event display crashing when showing PFCandidates
Add the HGCal calorimeter collections to the pileup mix, so that they're available for the pileup events
checkpointing work
start work on putting KDTree in arbor
working on speeding up arbor
Moving to the previos digi model used for phase 1 MC
arbor sped up by factor 100 in pileup situations
Add CFPosition to pixelDigSimLinks; use in hitAssociator
Merge pull request #4704 from mileva/from-CMSSW_6_2_X_SLHC_2014-07-18-0200_moveToPh1DigiModel_18Jul

Moving to the previos digi model used for phase 1 MC
Merge pull request #4715 from lgray/HGC-Linking

Massive HGC Clustering speed/memory improvements
Make associateHitbySimTrack a tracked param via existsAs
Fix merge conflicts from clash with #4714

Conflicts:
	SimTracker/SiPixelDigitizer/plugins/SiPixelDigitizer.cc
Copied over @wmtford's pixel digitiser changes to the Phase2 digitiser
Merge pull request #4738 from mark-grimes/resolve4716Conflicts

#4716 with merge conflicts resolved and Phase2 digitiser updated