[omx] Skip the resize when not needed when decoding jpegs

The decode to texture path almost always uses cached jpegs that are the correct size, so the resize is rarely needed.
The re-enc path usually needs resizing, but may not where the source is small.

Skipping the resize stage saves a little time and memory on GPU and also saves some setup time.
[hifiberry] Hack: force it to be recognised as IEC958 capable to enable passthrough options
[dvdplayer] Use inexact seeking like omxplayer
[omxplayer] Make use of TrueHD fastpath when downmixing

The TrueHD codec actually works in 3 stages. It decodes the downmixed stereo. It then decodes the differences required to produce 5.1.
It then decodes the differences required to produce 7.1.

Many users end up downmixing this 7.1 stream back to 2.0.
Much better to tell the codec we only need the 2.0 stream. It saves about 50% of the CPU required
[omxplayer] When in dual audio mode, make one output the slave

May help audio sync between the two outputs
 truehd: add hand-scheduled ARM asm version of mlp_filter_channel.

Profiling results for overall audio decode and the mlp_filter_channel(_arm)
function in particular are as follows:

              Before          After
              Mean   StdDev   Mean   StdDev  Confidence  Change
6:2 total     380.4  22.0     370.8  17.0    87.4%       +2.6%  (insignificant)
6:2 function  60.7   7.2      36.6   8.1     100.0%      +65.8%
8:2 total     357.0  17.5     343.2  19.0    97.8%       +4.0%  (insignificant)
8:2 function  60.3   8.8      37.3   3.8     100.0%      +61.8%
6:6 total     717.2  23.2     658.4  15.7    100.0%      +8.9%
6:6 function  140.4  12.9     81.5   9.2     100.0%      +72.4%
8:8 total     981.9  16.2     896.2  24.5    100.0%      +9.6%
8:8 function  193.4  15.0     103.3  11.5    100.0%      +87.2%

Experiments with adding preload instructions to this function yielded no
useful benefit, so these have not been included.

The assembly version has also been tested with a fuzz tester to ensure that
any combinations of inputs not exercised by my available test streams still
generate mathematically identical results to the C version.
truehd: break out part of rematrix_channels into platform-specific callback.

Verified with profiling that this doesn't have a measurable effect upon
overall performance.
truehd: add hand-scheduled ARM asm version of ff_mlp_rematrix_channel.

Profiling results for overall audio decode and the rematrix_channels function
in particular are as follows:

              Before          After
              Mean   StdDev   Mean   StdDev  Confidence  Change
6:2 total     370.8  17.0     348.8  20.1    99.9%       +6.3%
6:2 function  46.4   8.4      45.8   6.6     18.0%       +1.2%  (insignificant)
8:2 total     343.2  19.0     339.1  15.4    54.7%       +1.2%  (insignificant)
8:2 function  38.9   3.9      40.2   6.9     52.4%       -3.2%  (insignificant)
6:6 total     658.4  15.7     604.6  20.8    100.0%      +8.9%
6:6 function  109.0  8.7      59.5   5.4     100.0%      +83.3%
8:8 total     896.2  24.5     766.4  17.6    100.0%      +16.9%
8:8 function  223.4  12.8     93.8   5.0     100.0%      +138.3%

The assembly version has also been tested with a fuzz tester to ensure that
any combinations of inputs not exercised by my available test streams still
generate mathematically identical results to the C version.
truehd: tune VLC decoding for ARM.

Profiling on a Raspberry Pi revealed the best performance to correspond
with VLC_BITS = 5. Results for overall audio decode and the get_vlc2 function
in particular are as follows:

              Before          After
              Mean   StdDev   Mean   StdDev  Confidence  Change
6:2 total     348.8  20.1     339.6  15.1    88.8%       +2.7%  (insignificant)
6:2 function  38.1   8.1      26.4   4.1     100.0%      +44.5%
8:2 total     339.1  15.4     324.5  15.5    99.4%       +4.5%
8:2 function  33.8   7.0      27.3   5.6     99.7%       +23.6%
6:6 total     604.6  20.8     572.8  20.6    100.0%      +5.6%
6:6 function  95.8   8.4      68.9   8.2     100.0%      +39.1%
8:8 total     766.4  17.6     741.5  21.2    100.0%      +3.4%
8:8 function  106.0  11.4     86.1   9.9     100.0%      +23.1%
truehd: break out part of output_data into platform-specific callback.

Verified with profiling that this doesn't have a measurable effect upon
overall performance.
truehd: add hand-scheduled ARM asm version of ff_mlp_pack_output.

Profiling results for overall decode and the output_data function in
particular are as follows:

              Before          After
              Mean   StdDev   Mean   StdDev  Confidence  Change
6:2 total     339.6  15.1     329.3  16.0    95.8%       +3.1%  (insignificant)
6:2 function  24.6   6.0      9.9    3.1     100.0%      +148.5%
8:2 total     324.5  15.5     323.6  14.3    15.2%       +0.3%  (insignificant)
8:2 function  20.4   3.9      9.9    3.4     100.0%      +104.7%
6:6 total     572.8  20.6     539.9  24.2    100.0%      +6.1%
6:6 function  54.5   5.6      16.0   3.8     100.0%      +240.9%
8:8 total     741.5  21.2     702.5  18.5    100.0%      +5.6%
8:8 function  63.9   7.6      18.4   4.8     100.0%      +247.3%

The assembly version has also been tested with a fuzz tester to ensure that
any combinations of inputs not exercised by my available test streams still
generate mathematically identical results to the C version.
Enable PYTHONOPTIMIZE for Pi
[rbp] Hardware accelerated resampling

This replaces the format conversion, up/down mixing and resampling code from ActiveAE with a GPU accelerated version.
Should significantly reduce CPU when using paplayer or dvdplayer.

Requires updated firmware
[ffmpeg] Speed up wtv index creation

The index creation is O(N^2) with number of entries (typically thousands).
On a Pi this can take more than 60 seconds to execute for a recording of a few hours.

By replacing with an O(N) loop, this takes virtually zero time
[PiResample] Work around AE not providing correct src_bits
[windowing] Only need a confirmation dialogue when resolution has actually changed

This fixes a bug when every time video output settings page is opened it asks if you would like to keep this change
[rbp] Fix a leak in the failure handling of jpeg decode to texture