Switching default jet collection from AK5 to AK4

Here I have changed the default jet collection for downstream modules from AK5 to AK4. This affects : 
* b-tagging
* tau-tagging
* HLT
* PFBRECO
* Type1 MET
* Isolation cones.

I have not self-ported changes of hard-coded cone sizes from 0.5 to 0.4, except in the Jet RECO packages. There are probably pieces in BTagging and TauTagging code that use cone sizes and must change for consistency.