mythtv-vid: X11 Video output fixes branch

[danielk]

The point of the mythtv-vid branch is to fix some of the long standing deficiencies in the video output classes, for X11 in particular:

Filters

• Add support for OpenGL filtering, in particular Lanczos for scaling and YV12->RGB conversion for display (ref #843)
• Allow different filter sets for different video and display resolutions.
• Make setting up filters easier with a GUI
• Allow changing the filter set during playback, esp for deinterlacing.
• Auto-detect pull-up and apply ivtc filtering (#1778)

Video output methods

• Implement per-frame video resolution switching
• Support XvMC for MPEG-2 NUV files (and enable transcode to MPEG-2)
• Finish support for XvMC copy to pbuffer + opengl render
• Key xrandr switching to video framerate

OSD rendering

• Fix video frame OSD blending for bob-deint (Filter vert freq in pause + when there is video<->screen framerate mismatch)
• Implement RGB OSD surfaces
• Implement OpenGL OSD surfaces
• Implement X Composited OSD surfaces
• Key preferred OSD and OSD fade to resolution and video output method.