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

Hi @slava77 , we do not see major problems with the current version of the IO rule. It might not be elegant, but it passed the tests and it is likely to be used only for a very limited time during the transition to 72X. We think that after your other comments have been implemented this PR should be merged asap.