user-guide.pdf is about twenty years out of date

Need to update this documentation. I contacted Dr. Steven Rice, but unfortunately (read: unsurprisingly—it's been 20 years) they do not have the source for this document.

While we're at it, might as well publish this on [readthedocs.org](http://readthedocs.org/). It boasts automatically producing HTML, PDF, and ebook output!