Cleanup of Old MVA assignment + kill dead code

Built ontop of 700pre8 + patches, can rebase if needed.

Fix assignment of electron cluster and improve agreement of "mva" variable, you can see the improvement in agreement between mva values for (tracker-Driven && ECAL-Driven) electrons. The old mva-id isn't cut on anywhere in the ged reconstruction, so it is purely there for 

Also, removed a few hundred lines of dead code from PFEGammaAlgo.cc/.h, none of it was called so this is purely cosmetic.