video playback enhancements for Linux part1: vdpau

I have been working on this for quite a while and built dozens of prototypes. Now I think I have something worth for you to review. It is actually an almost complete re-write of vdpau. In order to get the most out of it I had to touch player and rederer as well.

- Performace improvements
Separate threads for deinterlacing, opengl interoperation, frame buffering in renderer. This maximizes time for decoding and deinterlacing. 

- Improved deinterlacing
The advanced methods now use 4 past and 2 future fields, instead of 2 past and 1 future. I have stutter free playback of 1080i@50, temporal/spacial deinterlacing on ION2

- Fix stuttering caused by overwrite (early reuse) of video surfaces