While waiting for the dust to settle on the POG version of the
MVA electron ID, make Heppy use the CMGTools implementation.
Note: this is a CMGTools commit, NOT to be pulled into Heppy,
even if it touches an Heppy package.
Heppy: Electron instance members must be reinitialized, since PyROOT seems to be recycling python proxies also for different objects