New jet flavour definition: Backport from 7_1_X to 7_0_X

Backport of #2395, #3025, and #3228.

**Update (Apr. 30, 2014):** PR rebased (to avoid conflicts with #3254) and extended by also backporting #3509 (integrates the new jet flavor into PAT) and #3601 (changes the data members of pat::Jet storing the flavor information)

**Update (May 9, 2014):** PR extended by also backporting #3785 which replaces runtime cms::Exception calls with edm::LogError calls in the jet flavour code