[rbp/omxplayer] sync up with dvdplayer master changes
Merge pull request #2372 from huceke/raspberrypi

[rbp/omxplayer] sync up with dvdplayer master changes
[rbp] Set mediatime on GPU after a seek.

Currently after a seek, the mediatime doesn't update until an audio and video packet have been fetched from demuxer, and been decoded. For HD content this can take a second or two.
This has a couple of undesirable effects:
The seek time that pops up after a seek initially shows the before seek time, and the file progress bar is laggy.
If you seek a second time, before the time has updated, it will use the before seek time, and the second seek has no effect.
This limits a sequence of seeks to a maximum of about 1 every second or two.

The fix udpates the GPU mediatime immediately after the seek, so the mediatime is correct immediately which fixes the undesirable behaviour.
Merge pull request #2537 from popcornmix/mediatime

[rbp] Set mediatime on GPU after a seek.
upnp: container updates weren't propagating to GUI for current path
VideoRenerers: add buffering
add buffering for GLES
WinRenderer: add buffering
DXVA: activate buffering in renderer
linuxrenderer: delete all textures on reconfigure
drop frame counter in application, ask render manager instead
vaapi: adopt to buffering in renderer
add buffering - some documentation
RenderManager: only flip free buffer if player has added something
move NUM_BUFFERS up to BaseRenderer.h
OverlayRenderer: align buffers with index in renderManager
add buffering - submit absolute time to render buffers
RenderManager: some rework to buffering
dvdplayer: disable buffering unil dropping is improved
RenderManager: skip very late frames in render buffer