Remove the starting zero from ANS CDFs.

This brings it in line with the Daala CDFs and will make it easier to
share code.

Change-Id: Idfd2d2b33c3b9b2c4e72ce72fb3d8039013448b9
(cherry picked from aom/master commit af98507ca928afe33e9f88fdd2ca168379528d6a)
5 files changed