Rappoccio : change EITopPag to use latest POG recommendations

There are a few changes to EITopPag which were requested by the Top PAG to bring this in line
with the POG recommendations. The delta-beta correction should be used for electrons with the
same cut as the muons. They also requested a b-tagging sequence be run. 

This requires a dataformats change to GsfElectron to include the pileup isolation that
is computed in RECO.