Vizer: Added in experimental max KF boost values.

Vizer: Added in experimental max KF boost values.

Added the experimental max per frame KF boost values derived from
the Vizier experiments.

These are still all off by default.

When enabled I expect these to cause significant regression as they
fluctuate wildly and in a way that makes no sense from format to format.

I suspect these values reflect over fitting perhaps from a subset of
training clips with more frequent mid chunk key frames and or short key
frame groups.

Also fixed incorrect value for gf boost for one format.

Experiment to moderate these values and use different values for first
and subsequent KF groups to follow.

Change-Id: Ibeb4268957f2edacdb4549d74930255a22a2fcc5