cleanup: remove c++ ref parameter on xWriteCoefRemainExGolomb
frameencoder: set QP to all parts of CU. No logic change.
remove unused trUnitIdx from subtract() and addClip()
Backed out changeset: 524fdbaed8d0

bits0 and bits1 include list[N].bits and thus they did include the list
selection bit costs.

--HG--
extra : amend_source : 141bd3b7aa7d289d5854372fa50238b1edb86d1f
TEncSearch: switch xGetInterPredictionError() to use SATD [CHANGES OUTPUTS]

predInterSearch() was having to remeasure the unidir/bidir prediction just
because it wanted to measure merge with sa8d.  By switching to satd, a number
of further simplifications can be made.
TEncSearch: refactor predInterSearch to avoid redundant work
TEncSearch: merge xGetInterPredictionError into xMergeEstimation
TEncSearch: remove redundant EMMS instrutions

predInterSearch uses no float operations, so a single EMMS at the end is
sufficient
TEncSearch: recombine merge-only path, now it can be accomplished with continue