[rbp/omxplayer] Fixes for trickplay

In #2955 we lied in GetTime when in trickplay modes to avoid jittery updates in elapsed time.
This was wrong when GetClock() didn't match the media time (e.g. when playback was started from a bookmark).

The jitter is caused by the DISPLAYTIME messages that don't really work on omxplayer.
Instead bypass the DISPLAYTIME messages and set the time explicity in OMXPlayer (using media time where appropriate).

Also in trickplay, do the seek/flush step more to fix an issue when going from normal to rewind after EOS

Also don't honour the "accurate" seek flag, as it results in corrupt frames being displayed
[rbp/omxplayer] Fix audio sync with visualisation

As GPU can buffer a few seconds of audio, and the visualisation is updated immediately, they are badly out of sync.
The solution is to push the visualisation data through a queue, and retrieve it from queue when the media time is reached.
[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.