The examples and learning plugins have outlived their usefulness, and
this repo already has substantial history in being a boids plugin. I'm
renaming the crate (and repo, but that isn't visible to git) to treat
this simply as a boids repo.
I ignored the use of sound because I don't want to download sound files.
I'm not certain that the `steppings` module is required, but I don't
really know what it does, either.
