NEON functions for lossless coding

Verified OK, but right now they don't seem faster.
So they are disabled behind a USE_INTRINSICS flag (off for now)

Change-Id: I72a1c4fa3798f98c1e034f7ca781914c36d3392c
MIPS: MIPS32r1: Added optimizations for FastLog2

Functions VP8LFastLog2Slow and VP8LFastSLog2Slow

also: replaced some "% y" by "& (y-1)" in the C-version
(since y is a power-of-two)

Change-Id: I875170384e3c333812ca42d6ce7278aecabd60f0
Merge "MIPS: MIPS32r1: Added optimizations for FastLog2"
NEON intrinsics version of FTransform

as little bit slower than inlined asm it seems.
So disabled for now.

Change-Id: I8c942846f9bedaed57275675ea9dbbcb8dfd9ccd
fix lossless_neon.c

* some extra {xx , 0 } in initializers
* replaced by vget_lane_u32() where appropriate

Change-Id: Iabcd8ec34d7c853920491fb147a10d4472280a36
replace some mult-long (vmull_u8) with mult-long-accumulate (vmlal_u8)

saves few instructions

Change-Id: If8f464bb2894a209bba94825a4db9267df126d47
NEON intrinsics version of CollectHistogram

apparently faster, but we might save some load/store to/from memory
once we settle for the intrinsics-based FTransform()

(also: fixed some #ifdef USE_INTRINSICS problems)

Change-Id: I426dea299cea0c64eb21c4d81a04a960e0c263c7
Merge "NEON intrinsics version of CollectHistogram"
WIP: extract the float-calculation of HuffmanCost from loop

new function: VP8FinalHuffmanCost()

Change-Id: I42102f8e5ef6d7a7af66490af77b7dc2048a9cb9
MIPS: MIPS32r1: Added optimizations for ExtraCost functions.

ExtraCost and ExtraCostCombined

Change-Id: I7eceb9ce2807296c6b43b974e4216879ddcd79f2
Merge "replace some mult-long (vmull_u8) with mult-long-accumulate (vmlal_u8)"
Merge "WIP: extract the float-calculation of HuffmanCost from loop"
enc_neon: cosmetics

fix/remove incorrect comments
+ whitespace

Change-Id: Id1b86beb23e5bf946e73c34ab7066b6ca177f33b
cosmetics:

* remove MIPS32 suffix from static function names
* fix a long line in enc_neon.c

Change-Id: Ia1294ae46f471b3eb1e9ba43c6aa1b29a7aeb447