[EGL] Fix the non-trivial dirty rectangle modes

EGL is typically double or triple buffered, and the previous buffer contents are not preserved.
This means the non-trivial dirty rectangle modes display a flickery mess.

EGL does provide a means for requesting the EGL buffer is preserved across calls.
It seems appropriate to request that when using dirty rectangle modes.

This PR makes algorithmdirtyregions 1 and 2 work on the Raspberry Pi.
It needs testing on other EGL platforms.
Merge pull request #3021 from popcornmix/dirty_rect

[EGL] Fix the non-trivial dirty rectangle modes
[ffmpeg] - backport - arm: Add VFP-accelerated version of synth_filter_float

               Before           After
               Mean    StdDev   Mean    StdDev  Change
This function   9295.0 114.9     4853.2 83.5    +91.5%
Overall        23699.8 397.6    19285.5 292.0   +22.9%

Signed-off-by: Martin Storsjö <martin@martin.st>
[ffmpeg] - backport - arm: Add VFP-accelerated version of int32_to_float_fmul_scalar

               Before           After
               Mean    StdDev   Mean    StdDev  Change
This function   1175.0   4.4      366.2  18.3   +220.8%
Overall        19285.5 292.0    18420.5 489.1     +4.7%

Signed-off-by: Martin Storsjö <martin@martin.st>
[ffmpeg] - backport - fmtconvert: Add a new method, int32_to_float_fmul_array8

This is similar to int32_to_float_fmul_scalar, but
loads a new scalar multiplier every 8 input samples.
This enables the use of much larger input arrays, which
is important for pipelining on some CPUs (such as
ARMv6).

Signed-off-by: Martin Storsjö <martin@martin.st>
[ffmpeg] - backport - dcadec: Use int32_to_float_fmul_array8

Signed-off-by: Martin Storsjö <martin@martin.st>
[ffmpeg] - backport - arm: Add VFP-accelerated version of int32_to_float_fmul_array8

               Before           After
               Mean    StdDev   Mean    StdDev  Change
This function    366.2  18.3      277.8  13.7   +31.9%
Overall        18420.5 489.1    17049.5 408.2    +8.0%

Signed-off-by: Martin Storsjö <martin@martin.st>
[ffmpeg] - backport - arm: Add VFP-accelerated version of imdct_half

               Before           After
               Mean    StdDev   Mean    StdDev  Change
This function   2653.0  28.5     1108.8  51.4   +139.3%
Overall        17049.5 408.2    15973.0 223.2     +6.7%

Signed-off-by: Martin Storsjö <martin@martin.st>
[ffmpeg] - backport - arm: Add VFP-accelerated version of dca_lfe_fir

               Before           After
               Mean    StdDev   Mean    StdDev  Change
This function    868.2  33.5      436.0  27.0   +99.1%
Overall        15973.0 223.2    15577.5  83.2    +2.5%

Signed-off-by: Martin Storsjö <martin@martin.st>
[ffmpeg] - backport - arm: Add VFP-accelerated version of fft16

               Before           After
               Mean    StdDev   Mean    StdDev  Change
This function   1389.3  4.2       967.8  35.1   +43.6%
Overall        15577.5 83.2     15400.0 336.4    +1.2%

Signed-off-by: Martin Storsjö <martin@martin.st>
[ffmpeg] - backport - dcadsp: Add a new method, qmf_32_subbands

This does most of the work formerly carried out by
the static function qmf_32_subbands() in dcadec.c.

Signed-off-by: Martin Storsjö <martin@martin.st>
[ffmpeg] - backport - arm: Add VFP-accelerated version of qmf_32_subbands

               Before           After
               Mean    StdDev   Mean    StdDev  Change
This function   1323.0  98.0      746.2  60.6   +77.3%
Overall        15400.0 336.4    14147.5 288.4    +8.9%

Signed-off-by: Martin Storsjö <martin@martin.st>
[ffmpeg] - backport - arm: Mangle external symbols properly in new vfp assembly files

Reviewed-by: Kostya Shishkov
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
[ffmpeg/patches] Add backported armv6/vfp optimisations
[rbp/omxplayer] Support frame advance (single step) with right arrow when paused
[rbp/omxplayer] Do we need discontinuity handling?

So far I've not seen what this is needed for and it does cause problems for some files.
[rbp/omxplayer] Fix build error in types for max

It seems there is a compile error when STDINT_H_AVAILABLE is not defined.
See: http://raspbmc.apt-get.eu/downloads/bin/xbmc/nightlies/xbmc-rbp-20130710.log
Avoid flushing fifos when audio/video fifos out of sync
[confluence] Use animated gif as a cheaper working spinner
[rbp] Add screenshot implementation that includes video layer