yuv: simplify framesize usage
input: drop unthreaded reader paths for simplicity
primitive: remove pixeladd_pp and TComYuv::addClip()

These were used by the old HM bidir search
TComYuv: remove unused removeHighFreq()
pixel: remove AVX2 vector class SAD primitives

These are superceded by assembly - the ASM doesn't use AVX2 yet but it's already
faster
cli: file writers should validate output bitdepth, if any is specified
TComPicYuv: remove unused dump function
TComPicYuv: cleanup prefixes
TComPicYuv: remove unused copy methods
TComPicYuv: remove unused luma-oriented functions, cleanup destroy method
csp: fix allocation size calculation of chroma planes
yuv: pic.stride should be in units of pixels, not bytes
TComPicYuv: add a comment for future optimizations