move public encoder and picture functions to api.cpp
api: check for NULL param pointer in x265_encoder_open
asm: add new file for 10bpp asm filter functions
asm: enable 10bit asm filter functions, fix test harness
refine MC - cleanup unnecessary code paths, reduce copies for non-WP uni-pred
reduce unnecessary CU data set/clear (no neighbor access)

mvd, mvpIdx, mergeIndex
lookahead: bug fix for b-adapt 0 cost estimates (closes #26)

don't overwrite lastNonB reference with current frame, 'lastNonB' state was
already replaced with current frame's lowres at this point.

it mostly affected b-adapt=0 but could have affected any of the modes if they
had not already estimated this particular P frame cost before this point.
remove redundant state m_avgQpRc from TComSlice.

This has been moved to TComPic already.