Merge pull request #118 from fritsch/master

xvba: Set picture_structure to match the spec
ffmpeg xvba: fix vc1 field interlace
xvba: fix vc1 field interlace
xvba: vc1 - honor psf
ffmpeg xvba: honor psf
ffmpeg: register vdpau hwaccel for mpeg12
vdpau: move vdpau into hwaccel
ffmpeg: fix vdpau vc1 field interlace