Improvements to help with mythtv integration

I have been building MythTV frontend to work on a MELE A3700 and I have built it with VDPAU support for the MELE.

I have made the changes in the pull request and MythTV runs, but doesn't display anything yet as I get these printed on the console.
```
[VDPAU SUNXI] vdp_output_surface_render_bitmap_surface called but unimplemented!
[VDPAU SUNXI] Requested unimplemented picture_structure
```
Any help would be appreciated.

Thanks, and great job so far!