findrpt.icn: Program to find smallest repeat in a repeat pattern

This program produces the smallest motif in an image that will tile
to the image.

The image to be processed must be a "true" repeat -- pixel for pixel.

The options supported are:

     -n s    suffix for output image, default _t.  The suffix is
             appended to the basename of the input image, as in
             foo.gif -> foo_t.gif.

     -s      show size; default produce image

Warning:  This program is *very* slow.