

This program will take 3 image files  (assumed to be in the range of
0-255) and combine them as Red, Green, and Blue color components.  It
then quantizes these using Paul Heckbert's Color Quantization method
[Siggraph '82 proceedings, pp. 297-307] down to around 256 discrete colors
and creates a color table for it.  The method is also refered to as
Median Cut which is why the name i.median.

The results are similar to i.composite except that:

    results are in range 0-255 so it can be displayed in float mode
on monitors that can handle it (SUNVIEW can! if you first set
GRASS_COLOR256 environment variable.)  This is important, as the
fixed color table does a poor job of representing colors from this program.

    The algorithm used produces nicer images when combining 
color components from true photos (as opposed to multispectral
data) like nhap, or rgb components from image processing systems.
