Renamed 'utility'
Newer version, although its running terribly slow.
Its not as slow as I thought; I was making larger circles than the
previous benchmark. I did some tests, and found that using channels as generators is a horrible idea.
I'm about to try to standardize the tool so it can work in a pipeline;
each call to the tool will only apply one size circle, but can be
applied to an existing image. My goal is to allow something like

cat source.png | filter -n 100 -r 100 | filter -n 200 -r 10 > result.png

to apply 100 circles of radius 100 and 200 circles of radius 10.
Added a more robust set of command line options; the number, size, and opacity of approximations can now be set, along with the random number seed.
Fixed a small bug related to the bounds of the image
Added patching logic.