This commit fixes the lack of palettized display of 1-bit video
in the qtrle decoder. It is related to my commit of
lavf/qtpalette, which added 1-bit video to the "palettized video"
category. As far as I can see, everything works fine, but comments are
of course welcome.

Below are links to sample files, which should now be displayed properly
with bluish colors, but which were previously displayed in black &
white.

Matroska:
https://drive.google.com/open?id=0B3_pEBoLs0faNjI0cHBMWDhYY2c
Earth Spin 1-bit qtrle.mkv

QuickTime (mov):
https://drive.google.com/open?id=0B3_pEBoLs0faUlItWm9KaGJSTEE
Earth Spin 1-bit qtrle.mov
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>