sao: remove frame-based SAO
rd: move lambda and analysis qp init to rdcost.h

This will make it possible for Search instances to copy QP data between each
other
TComDataCU: replace getZorderIdxInCU() with encodeIdx of CU structure
TComDataCU: replace getTotalNumPart() with CU structure details
rc: apply maxAU size restrictions while encoding each frame
blockfill_s_16x16 avx2 asm code: performance improved from 389.21 cycles to 204.38 cycles, over sse version of asm code
blockfill_s_32x32 avx2 asm code: performance improved from 1354.05 cycles to 705.81 cycles, over sse version of asm code
asm: avx2 assembly code for idct4x4