cmake: use -DHAVE_ALIGNED_STACK=1 when building asm for Xcode

This matches the command line we use in the Makefile, and prevents stack
corruption when debugging within Xcode
pixel-a: fix x64 calling convention for several HEVC satd functions

Bug fix from Min Chen
log: collect statistics after CU analysis

Report percentage of CU blocks encoded at each depth of P/B slice as EncCU
cli: fix final stat line handling of optional PSNR and SSIM stats