plat.icn: Program to create image file with specified colors

This program produces image files from color lists, in which the
image file contains one pixel for each color.  The image files are
16x16 pixels.  If a color list has less than 256 colors, the rest
of the image is black.  If the color list has more than 256 colors
only the first 256 are processed.

The image file names have the basename of the color list files followed
by _p and the suffix .gif.