Forward porting MVA eelctron ID from 62X, part I.
Forward porting MVA eelctron ID from 62X, part II.
Forward porting MVA eelctron ID from 62X, part IIa.
Remove obsolete photon stuff.
Update partially for 70X.
Remove more obsolete stuff.
Merge pull request #1453 from vadler/70X-addMVAElectronId

70X Forward of porting MVA electron ID from 53X.