VideoRenerers: add buffering
add buffering for GLES
WinRenderer: add buffering
linuxrenderer: delete all textures on reconfigure
vaapi: adopt to buffering in renderer
add buffering - some documentation
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
renderbuffers: drop enable/disable in this iteration
RenderManager: add method SetSpeed
RenderManager: return bufferlevel with WaitForBuffer
RenderManager: do not drop in renderbuffers, this ruins detection of displayed frame
OMXPlayer: adapt to buffering