Match the use of AV_PIX_FMT_PAL8 for 1-bit QuickTime Animation in
lavc/qtrle. To reiterate, 1-bit video is not necessary black & white in
QuickTime, merely bi-level. The two colors can be any color. The palette,
either included in the sample description, or the default Macintosh
palette (black & white for 1-bit video) will be set in lavf/qtpalette.
See the QuickTime File Format Specification for details.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>