Nathan E. Egge authored Dec 26, 2018 and Ronald S. Bultje committed Jan 25, 2019

All of the msac decode functions use 15-bit CDFs with the exception of
msac_decode_bool_prob() which takes a (15 - EC_PROB_SHIFT)-bit
probability.
This patch internalizes the reduction in precision from the EC_SMALL_MUL
experiment (hiding the define) and gives msac calls a consistent API.