Fix a system-breaking typo

Somehow I didn't notice that I'd written "success" as "sucess", which is
rather strange as I thought I'd used the `rcfiles` script to update
everything (which would have failed with this typo). Guess not! I'm
sorry everybody, I shall make my penance.
Add a license and a README

Naturally, to the extent possible, I've licensed things under an
MIT/BSD-style license. The README should be fairly exhaustive, or at
least exhausting to read, and at least tells you why this repository
exists and (basically) how to use it. That's good enough for now, I
suppose.