Increase gamma Et threshold for tau reco&id

[mbluj]

As title of the PR says, this is a set of modification of python cfi/cff files to increase Et threshold of PF-photons used in tau reconstruction and identification from 0.5 to 1GeV.

The modification is expected to have the following effects:

• momentum (and thus Pt) of reconstructed taus will be slightly smaller,
• some, but rather small, migration from decay modes with pi0's to decay modes without pi0's (1p+pi0->1p and 3p+pi0->3p)
• smaller values of photon related isolation sums, etc.

Expected changes are summarized in slides which can be found here: https://indico.cern.ch/event/671551/#8-performance-of-tau-recoid-wi