Original commit message from CVS:
Make it compile against latest CVS of FFMPEG:
* Put gst/gst.h above avcodec.h because it needs some types defined in glib.h
* Remove HQ (removed from lavc) property

Also add some functions to make SVQ1 decoding work:
* Add YUV9 colorspace
* Let lavc do its own buffer allocation and copy from there instead of using
our own buffer allocation functions. Somehow, that breaks. I don't know
why.