Substantial reworking of the speed vs quality trade offs for
speed 1 and 2.

In this patch I am attempting to freeze the "quality" meaning of
speeds 1 and 2 relative to speed 0 so that in future we can
better evaluate progress.

I am targeting :
Speed 1 quality ~-5% vs speed 0.
Speed 2 quality ~-10% vs speed 0

It is inevitable that quality will still fluctuate a little as we adjust
settings and add new features, but we will attempt to keep as
close as possible to these values. Above speed 2 things will remain
a bit more fluid for now.

In this patch speed 1 is approximately 4-5x as fast as speed 0. This
is similar to before but the quality hit is a lot less. Likewise speed 2
is approximately 2x as fast as speed 1 but is similar in quality to the
previous speed 1 configuration.

Also slight change to behavior of FLAG_EARLY_TERMINATE to insure
all reference frames get at least one rd test. Important for very low
variance regions.

WIP :- Added a new speed level with old speed 4 becoming speed 5.
Speed 3 and 4 tradeoffs still WIP

Change-Id: Ic7a38dd7b5b63ab1501f9352411972f480ac6264

This commit causes use last partition to consider whether a 64x64 has
motion that might make a new partitioning worth while.

Change-Id: I3a57bedef4f3cd961fadbfa96651c206fa36da4a

Adding appropriate test vector vp90-2-06-bilinear.webm.

Change-Id: Ia3bbf57318e0cc61a1b724fe751e3f9c7e11b337

Change-Id: I401536778e3c68ba2b3ae3955c689d005e1f1d59

Making appropriate memset inside decode_block now.

Change-Id: I8e944194668c830de08271c8fb6e413251c201d8

Remove mode_check_freq and mode_test_hit_counts from VP9_COMP.

Change-Id: Iabfd9f841444cd9bf19ac761a9795f140082ce0b

The codec should effectively run with motion vector of range (-2048, 2047)
in full pixels, for sequences of 1080p and below. Add assertions to clarify
this behavior.

Change-Id: Ia0cac28249f587d8f8882205228fa480263ab313

Change-Id: I4b1c6bb9ff615f5872b96ed07dbf0f5e18e63643

Change-Id: I92fd32476c472e54f52b8d7602a98262b25e6eaf

Change-Id: Ib19dabe697656e4d7e8403d91bedca7cd31d36bf

Change-Id: Icc6a76a5be77f3e19918155bab3998e0aa32ccf5

Change-Id: I6c4058aebe834e1a12b7a3fb10484b9ebe60b349

Change-Id: I84209d382ca5dfc537ee533cd792d8caa0e25cee

The declaration of the bilinear filters specified an alignment clause
in the implementation file but not in the header.  This turned out
to be harmless, but it did cause linker warnings to be emitted when
building on Windows.

The (extern) declaration in the header was changed, to match the
declaration in the implementation.

Change-Id: I44be89b1572fe9a50fa47a42e4db9128c4897b04

Interleaved the instructions, reduced register dependency, and
prefetched the source data. This improved the decoder speed
by 0.6% - 2%.

Change-Id: I568067aa0c629b2e58219326899c82aedf7eccca

Also renaming mb_row -> mi_row, mb_col -> mi_col arguments and calculate
mb_rows/mb_cols values from mi_rows/mi_cols.

Change-Id: I6919a279f560648e23bc9a12f507d17c21ffd5d7

near is a key word, changed to use nearmv instead.

Change-Id: Ib54438c431b2b2521a62fc7b61a9c127dd7bc01e

Change-Id: I6973e7121b6393379b5759f288632e8eab763d3e

Function list:
  tx_counts_to_branch_counts_32x32
  tx_counts_to_branch_counts_8x8
  tx_counts_to_branch_counts_8x8
  update_ct
  update_ct2
  update_mode_probs

Change-Id: I120d8945a34378cf285d6bd415e23de1d522cf2f

Make encoder skip rectangular partition check in speed 1 and above,
when early termination was triggered in partition split.
Thanks Guillaume (gmartres@) for catching this issue.

This change makes bus_cif at 2000kbps speed 1 runtime goes down from
25612ms to 23438ms (about 9% speed-up), at the expense of -0.235%
performance down.

Change-Id: I98613fad081a261d30d5fa206f934ca70601c180

Change-Id: I7380a089105f658257bbb3e30a525da168e76952