Palettized QuickTime video in Matroska has hitherto not been recognized
whatsoever, and the "palette" used has been completely random.

The patch for matroskadec.c fixes this issue by adding a palette side
data packet in matroska_deliver_packet(), much in the same way as it's
done in mov.c.

Video samples for testing are available at
https://drive.google.com/open?id=0B3_pEBoLs0faWElmM2FnLTZYNlk.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>