[rbp/omxplayer] Move buffering to omxplayer level

We wait to pause the clock when the queue of audio data to GPU is dangerourly low to avoid stuttering audio.
Better to pause for a few seconds and then play some intelligible audio, than to continuously underrun.
[rbp/omxplayer] Move the buffer of the decoded audio to output port

The buffers between host and gpu components are duplicated, so 2 seconds of 8 channel 48kHz audio requires 3MB.
That memory is required on both host and gpu. We want this buffering to provide protection from underrun when the arm is busy.

By moving the majority of the buffering from omx_decoder's input to output port, we save that memory on the arm.
Also the output port is 16-bit integer, rather than float, so we halve the size in addition.
[rbp/omxplayer] Remove clock manipulation from a/v players
[rbp/omxplayer] Move start flags out of clock component

Keep track of start flags locally. I believe the behaviour is unchanged now that clock state is controlled only by OMXPlayer.
[rbp/omxplayer] Remove unused function OMXStart
Merge pull request #2920 from ScudLee/tvshownfofix

Fix for tvshow.nfo being ignored on refresh
Merge pull request #2921 from ScudLee/caselesstvshowmatching

[Fix] Ensure tvshowmatching regexes are run caseless
Merge pull request #2875 from Montellese/swig_python_properties

[codegenerator] python: add support for class variables
interfaces: add ILanguageInvoker and ScriptInvocationManager
python: implement CPythonInvoker (replacing XBPyThread)
XBPython: cosmetics
python: let XBPython implement ILanguageInvocationHandler
cosmetics: remove trailing spaces from XBPython.h/cpp
python: register XBPython for .py files
use CScriptInvocationManager instead of XBPython
[win32] update VS project files
Merge pull request #2916 from afedchin/fix_intel_dxva

[win32] fix: best dxva deinterlacing on Intel platforms.
[gui] focus default control for pvr dialogs
Merge pull request #2912 from xhaggi/pvr-refactor-and-focus-fix

[gui] refactor and focus fix for pvr dialogs
[cosmetics] indent