Substantial restructuring of AQ mode 2.
The restructure moves the decision into the rd pick modes loop and makes a decision based at the 16x16 block level instead of only the 64x64 level. This gives finer granularity and better visual results on the clips I have tested. Metrics results are worse than the old AQ2 especially for PSNR and this mode now falls between AQ0 and AQ1 in terms of visual impact and metrics results. Further tuning of this to follow. It should be noted that if there are multiple iterations of the recode loop the segment for a MB could change in each loop if the previous loop causes a change in the complexity / variance bin of the block. Also where a block gets a delta Q this will alter the rd multiplier for this block in subsequent recode iterations and frames where the segmentation is applied. Change-Id: I20256c125daa14734c16f7cc9aefab656ab808f7