TrackBase & HitPattern redesign discussed on the RECO meeting of 08/05/2014

Documentation about the changes:
* https://twiki.cern.ch/twiki/bin/viewauth/CMS/TrackingHitPatternRedesign
* https://indico.cern.ch/event/327055/contribution/6/material/slides/0.pdf

I thought that the plan from the last iteration of this PR was to use a simple copy of bits instead of doing full unpacking into DetIds and then packing it back into bits.