x86: sbrdsp: implement SSE2 qmf_pre_shuffle

From 253 to 51 cycles on Arrandale and Win64.
44 cycles on SandyBridge.
x86: sbrdsp: implement SSE2 qmf_deint_bfly

From 312 to 68 cycles on Arrandale and Win64.
Sandybridge: 47 cycles.

Having a loop counter is a 7 cycle gain.
Unrolling is another 7 cycle gain.
Working in reverse scan is another 6 cycles.
x86: sbrdsp: implement SSE2 hf_apply_noise

233 to 105 cycles on Arrandale and Win64.
Replacing the multiplication by s_m[m] by a pand and a pxor with
appropriate vectors is slower. Unrolling is a 15 cycles win.
A SSE version was 4 cycles slower.
sbrdsp: unroll sbr_autocorrelate_c

1410 cycles to 1148 on Arrandale/Win64.
sbrdsp: unroll and use integer operations

This patch can be controversial, by assuming floats are IEEE-754 and
particular behaviour of the FPU will get in the way.
Timing on Arrandale and Win32 (thus, x87 FPU is used in the reference).

sbr_qmf_pre_shuffle_c: 115 to 76
sbr_neg_odd_64_c: 84 to 55
sbr_qmf_post_shuffle_c: 112 to 83
x86: float dsp: butterflies_float SSE

97c -> 49c
Some codecs could benefit from more unrolling, but AAC doesn't.
fate: aac: test subsampling in QMF synthesis

Add a mp4 file from the conformance suite, without renaming it.
The PCM file was generated by forcing CPU flags to mmx, but seems to differ
a lot from the wav file of the conformance suite.
x86: sbrdsp: implement SSE qmf_deint_neg

From 133 to 59 cycles on Arrandale/Win64.
autocorrelate