[rbp] Add screenshot implementation that includes video layer

As Pi doesn't use GL for video, a screenshot only contains UI.
Need to use Pi specific function for screenshot.
First implementation of the CRenderCapture interface

RenderCapture implementation for RPi using DispmanX

Minor changes that I reverted to the repo's version

Changed snapshot taking to use g_RBP.CaptureDisplay()

Removed unused fields, and changed implementation to use the width and height parameters
droid: cosmetic cleanup of dangling spaces
Use utf8 for text pasted from the clipboard
Remove 'Go to settings' Context menu from FileManager
Dont show 'Select all' in context menu, if everything is already selected
Merge pull request #3053 from jhsrennie/paste_utf8_2

Use utf8 for text pasted from the clipboard
Merge pull request #2807 from Fice/filemanager_context_cleanup

[Context Menu] Filemanager context menu cleanup
Merge pull request #3023 from popcornmix/screenshot

[rbp] Add screenshot implementation that includes video layer
Merge pull request #3020 from brooc/master

RenderCapture implementation for RPi
[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] Switch from libshairport to libshairplay for airplay
[rbp/omxplayer] Support both analogue and hdmi audio

Thanks to stupid-boy for original implementation.
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%