2/24/93 (Version 1.1)

Now the random dither is always enabled now (used to be enabled only
with -r); now disabled with -nr.

The Red/Green/Blue gamma is now at 1.0 for default values (turns out
that color correction is useful for our Digital monitors).

Added a new colorspace conversion function to make the displayer
compliant with H.261 and MPEG specifications; this is the CCIR 601
digital conversion.  The JPEG JFIF YUV->RGB mode is used default; the
CCIR YUV->RGB mode can be specified with -C.

Changed the decimation calculation routine to be more correct.