Independent horizontal and vertical implementations.

Requires that blocks be built from 4x4 and [xy]_step_q4 == 16

6-10% improvement. CIF improved the least.

Change-Id: I137f5ceae4440adc0960bf88e4453e55a618bcda

Change-Id: Iae84ab945cc9662a0ddd839aa2b9ca59f2ae5423

Change-Id: I3ce849452ed4f08527de9565a9914d5ee36170aa

Change-Id: Ia942e56cf322821d42ba06178672791eeee2847e

Where possible, do the 16 pixel wide filter while doing the horizontal
filtering pass. The same approach can be taken for the mbloop_filter
when that's implemented. Doing so on the vertical pass is a little more
involved, but possible.

Change-Id: I010cb505e623464247ae8f67fa25a0cdac091320

Change-Id: I0543e72fa092eef3976b65e16bb597197c364873

This commit fixed the mis-use of the tx_type for inverse transform
in intra4x4 rate-distortion optimization loop. It improves the
overall coding performance.

Change-Id: I7fe9953175b74890357dbcee33c138573766e980

Change-Id: Ic5257fa8278e9b6297de230e4fd26a1e23ad2bb7

Change-Id: I5dea4570cb05df27a522abf6e7b695998654284a

Change-Id: I2d22577911a37ed7d8c7e08cac20764842267652

Change-Id: I30a597c0cc366e34c9a3e2afe32d70e044f95ca4

Change-Id: Ie0cb732fdcb98616a422c4463bff80642248d136

Adds a speed feature to eliminate full-rd computation if the modeled
rd or rd based on a different parameter in the same mode is already
a lot larger than the best rd yet.

Specifically, only search the sharp and smooth filters if the modeled
rd cost based on the  regular filter is within a certain factor of the
best rd cost so far. Also, skip full-rd computation of non splitmv
inter modes if the modeled rd cost based on pred error is within the
same factor of the best rd cost so far.

Also adds some enhancements in the rd search for splitmv mode to
speed things up by early breakouts. Negligible impact on performance.

Resuts on derfraw300:
psnr:    -0.013% with the splitmv enhancements, -0.24% with the rd
         breakout feature on.
speedup: 6% with splitmv enhancements, 20% with also residual breakout
         (tested on football sequence at 600 Kbps)

Change-Id: I37abc308ea9f110c1679ce649b6a7e73ab1ad5fc

This commit enables 16x16 ADST/DCT forward hybrid transform using SSE2
operations. It reduces the runtime from 5433 cycles to 1621 cycles, at
no compression performance loss.

Change-Id: I75fd7f1984e9e28846af459f810ff0d6ae125230

Splitting setup_txfm_mode into read_tx_mode and read_tx_probs.

Change-Id: I5b4fe48698d56490857d32eafcaeb4291f208479

Unit tests on the functional accuracy of forward ADST/DCT.

Change-Id: I81afff866bdeacbd457b0af96993a035741657f6

Change-Id: Iad70966b986f65259329070e258f76ef0af816b4

Change-Id: I3441c059214c2956e8261331bbf521525a617a86