Backport 71x fixes to 70x branch

Backporting tau bugfixes made since CMSSW_7_0_0 that are already included in 71x. See #2449 and #2843. This configuration has also been checked on Fall13 samples (https://indico.cern.ch/event/307553/contribution/3/material/slides/0.pdf) and behaviour is as expected. 

The quality cuts update from #2843 (that improved performance) is not included, but it can be included as well, if you would like to speed-up the RECO sequence.

@slava77, @davidlange6, sorry for not presenting this proposal at RECO meeting, but last week was I think cancelled, and next one is on Thursday. As a result, we are open to discussion of what should be contained in this backport.

@monicava, this is something you want to watch as well