Merge with default (feature freeze for 0.6)

Bug fixes and tunings only on the stable branch, until the
next tag is issued.
intra: fix yasm warning about redefined macro
vec: remove scale2D_64to32, we have asm coverage
vec: remove intra_pred_planar16_sse4, we have asm coverage
cmake: detect inttypes.h and use for uint64_t printfs
Merge with stable