[rbp/omxplayer] Support both analogue and hdmi audio

Thanks to stupid-boy for original implementation.
[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.

I've also added a small weight to higher multiples of the desired framerate, so if display supports 30, 60 and 120Hz
and the video is 30fps then 30 will now be chosen rather than 120. This reduces the overhead of rendering the gui.
[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.
Add missing h264dsp initialisation call

Each AVStream struct for an H.264 elementary stream actually has two copies
of the H264DSPContext struct (and in fact all the other members of
H264Context as well):

((H264Context *) ((AVStream *)st)->codec->priv_data)->h264dsp
((H264Context *) ((AVStream *)st)->parser->priv_data)->h264dsp

but only the first of these was actually being initialised. This prevented
the addition of platform-specific implementations of parser-related functions.
New h264dsp method, h264_find_start_code_candidate

This performs the start code search which was previously part of
h264_find_frame_end() - the most CPU intensive part of the function.
arm: Add assembly version of h264_find_start_code_candidate

               Before          After
               Mean   StdDev   Mean   StdDev  Change
This function   479.8  16.7     181.0  11.1   +165.1%
Overall        2898.0  24.4    2738.2  26.3     +5.8%
[OverlayRenderGL] Fix corrupt pixels in graphical subs

On Pi you can see a corrupt line of pixels on bottom and right edges of subtitle bounding box.
This is due to incorrectly calculated texture coordinates fetching one pixel beyond valid texture.
[rbp/omxplayer] Cosmetics
[utils] Speed up sorting code used by library views

Sort a table of references to maps, rather than shuffling the maps themselves.
Should speed up time taken to enter library views like movies.