GED EGM RECO as default + customizeOldEGReco

This is built on top of CMSSW_7_0_X_2013-12-18-1400.

You will need to manually download the new MVA weight file, for the classifiers, in the following packages:
RecoParticleFlow/PFTracking
RecoEgamma/ElectronIdentification

with the usual ```cat download.url | xargs wget```

For comparison purposes the default running mode of this PR should be a no-op to "GED mode" for #1801.
Likewise "OldEG" mode should be a no-op to the default running mode from before #1801, except for tracker-driven only GSF electrons where we cannot use the old soft-electron MVA or or converted brem finder. This leads to a slightly increased fake rate.

I've updated FastSim and Skims where necessary.

OldEG mode is activated by doing:
```runTheMatrix.py -s --useInput all  --command="--customise RecoEgamma/Configuration/customizeOldEGReco.customizeOldEGReco"```

@slava77 The default mode only runs one version of the of conversion tracking. Please confirm timing improvements. The OldEG mode runs both sets of conversion tracking now.
@nancymarinelli In default mode, standard reco::Photons no longer have conversion information. 
@franzoni All validation sequences (that I could find) have been updated to point at the new ged products. If there's anything deeper you need please let us know.

Matrix tests on my side:
- default mode is fine
- customizeOldEGReco works fine