Readme and docs rewrite

This is essentially a rewrite of the docs. Some of the documentation is basic, but was similarly basic before.

This incorporates content from a few of my blog posts, and some unpublished blog posts.

Because I was doing a complete rewrite, I did a rename on README to README.md, and added a symbolic link to keep autotools happy.

The diffs aren't very meaningful, as most of the content is new.