Add some sort of testing and benchmarking

[z0w0]

Unit testing things like the color composing functions is obvious, but I'm not too sure how to automate testing the rendering functions, although it could definitely be done by creating a PNG surface, using that to render and then comparing the final output to a static PNG file.

There also needs to be benchmarking so potential optimizations can be spotted and made.

[z0w0]

I'm going to close this. There's unit tests for stuff that needs it. In the case of things like automatons and signal utilities, usually you can be sure enough that it's working if it compiles.