slicetype: hard-code 8x8 CU size for intra predictions output buffer
TEncSearch: replace getLumaFilterBlock() use with fpel getLumaAddr()

This returned address is stored in m_distParam but it never actually used. The
fref is overwritten before any calls to SATD
TComPicYuv: remove getLumaFilterBlock() methods, generate on demand in subpel

TEncSearch::xPatternRefinement() is only used for bidir refinement, and is on
the short-list to be removed once bidir is optimized.
TComRdCost: remove step parameter, always 1, merge setDistParam methods
TEncSearch: remove m_bc and inline xPatternSearchFracDIF
TEncSearch: fix a typo
TEncSearch: use optimized satd primitives for bidir fractional search
TEncSearch: simplify refPic initialization
x265: disable weighted bipred CLI option