no-rdo early exit: giving weightage to the cost of all CU's and neighbour CU's for early exit

Early exit is done when CU cost at depth "n" is lessthan sum of 60% of avgcost of all CU's
and 40% of avgcost of neighbour CU's at same depth.
asm: pixel_avg_32x(64,32,24,8)
asm: pixel_avg_64x(64,48,16)
asm: asm: pixel_avg_24x32
asm: pixel_avg_48x64, pixel_avg_8x32
cleanup: hardcoded m_qtTempTComYuv[qtLayer].m_width to MAX_CU_SIZE
Backout: Causing non-determinism in rd 0 and 1. Needs to be further investigated.