This commit reworks the transform and quantization unit. It enables
the use of adaptive quantization for intra modes. This further
improves the compression performance:
lowres 0.36%
midres 0.79%
hdres  0.73%

The key frame coding performance is improved:
lowres 1.7%
midres 1.9%
hdres  3.3%

The overall coding gains are:
lowres 1.1%
midres 1.8%
hdres  2.3%

Change-Id: Iaec1a3a4c1d5eac883ab526ed076d957060479dd