fix for the number of weighted references exceeding 8 in HM weight analysis

--HG--
branch : stable
slicetype: fix for gcc warnings
Merge with stable
cmake: fix Win64 vector primitive compile flags
picel: fix compile error from older gcc
cleanup: removed unused code from sad-a.asm
asm: removed unused function defnitions from pixel.h
rc: fixups for cutree changes
asm: move cvt* functions to blockcopy8.asm
asm: remove more unused funcdefs from pixel.h
asm: move transpose from pixel-a.asm to pixel-util8.asm, add pixel-util.h
asm: move SSIM functions to pixel-util
asm: move scale functions to pixel-util

--HG--
extra : amend_source : 024806e984b575527af426d82f07d8e6354ffb0e
pixel: remove an unused macro
asm: move pixel_sub to pixel-util8.asm, move pixel_avg funcdef to mc.h
asm: move variance functions to pixel-util8.asm
asm: move ssd functions into their own ssd-a.asm file, similar to sad-a.asm
asm: make it more clear that pixel-a.asm has only satd and sa8d now