Support playing SMV files.

Audio and video are interleaved via stream cur_dts - no idea how
reliable this is.
It also cannot display the video properly - it is stored with
about 15 in a single JPEG frame, I cannot think of a reasonable
way to implement this.
Samples: http://samples.mplayerhq.hu/smv/
Format description: http://wiki.multimedia.cx/index.php?title=SMV



Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>