Adds a tool for random improvement probing
Adds a tool for random improvement probing

This tool is intended to find improved encodings for the files and rates
used in the test set, across all codecs.

google/compare-codecs,alvestrand/old-compare-codecs,alvestrand/old-compare-codecs,google/compare-codecs,ruil2/compare-codecs,alvestrand/old-compare-codecs,ruil2/compare-codecs,google/compare-codecs,ruil2/compare-codecs,google/compare-codecs,alvestrand/old-compare-codecs,ruil2/compare-codecs,ruil2/compare-codecs,google/compare-codecs