Fix crash when exiting LiveTV

This can occur mostly when liveTV is started using mythavtest. Should playback fail for some reasons and we exited: kaboom
Use new render2/hwaccel VDPAU api

Hopefully, no more changes in the VDPAU Ffmpeg API (3rd in 12 months).
Fully remove the original VDPAU api, as it causes memory corruption from time to time. Hwaccel is the way forward anyway.

Tested with nvidia (both nouveau and proprietary) and AMD cards.