Mid-term: Movie playback support.

[mauvecow]

A lot of games use movie playback support, but due to portability reasons I do not believe we can get away with anything but Theora support for the time being.

Needed:

• Shaders for YUV rendering on the hardware side of things.
• Interface and code for managing playback, control, and display of movies.
• Implementation of a framework for handling different movie playback sources.
• Theora support.

Nothing too bad, I believe, but it would be my first time handling code like this so an investigative period is needed.