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

Well, if instead of a few-line implementation, you eventually chose to go a very long way.
Now that it's in this state, I guess no big point to argue.

The problem is that this rule will stay here and will need to be maintained if someone decides to reorganize the interface to DetIds.
Hopefully that will happen when we can abandon this translation rule and give up on support of the old format.