[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
[PiResample] Work around AE not providing correct src_bits
[rbp/omxplayer] When opening a stream don't try to update gui so often
[omxcodec] Clamp video texture at edges to avoid image wrapping
[PiSink] Remove unneeded header and use CAEChannelInfo directly
[omxplayer] Remove PCMRemap and handle multichannel mixing like ActiveAE does
[omxplayer] Make the sharpness control act as a sharpness control.

This fixes scaling kernel as Mitchell Netravali, and varies sharpness over range B=[5/3,0] C=[-1/3,1/2]
[omxplayer] Don't propagate 3d flags based on supported 3d modes
[graphics] Don't set stereo mode based on resolution

The resolution change should follow stereo mode
[graphics] Allow switching to a more suitable 3D resolution
[3D] Support switching to 3D resolutions

Include matching 3D flags (SBS/TAB) in the score of a resolution to switch to, to enable switching to 3d modes.
Also remove the old code that treated 3D modes differently when assigning a score.
[graphics] Make pixel ratio for 3d modes consistent

Note: Use the stored stereo flags from lists of resolutions.
Use current stereo mode for current resolution.
[PiSink] More attempts to reduce underrun audio glitches with multichannl and high samplerate
[omxplayer] Make dvdplayer the default for dvd images
[cec] Don't suspend pi on tv switch off - it can't wake up
[confluence] Use animated gif as a cheaper working spinner
[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] Avoid marking non-monotonic timestamps as unknown

Following a single spurious timestamp that is in the future,
all subsequent timestamps will be marked unknown causing out of sync.
ffmpeg demuxer: faster channel change for PVR addons without internal demuxing
Add time taken to resample to log