This experiment aims at merging lbd/hbd txfms

So far this exp uses hbd transform on lbd path.
The performances I observed are
lowres -0.089%
midres  0.065%
(negative means performance drop)

Started from here, two main things are needed to be done.
1) Fix overflow due to quantizer noise
2) Generate a 16-bit version from the hbd txfm

Change-Id: I35bb1fc0cbb78decad2570ff5826ed665f739752