Wikify

This includes the changes from PR #65 by @mdw, plus a whole bunch of new documentation, and a complete revamp of the README.md.

You can see what a radical difference it makes:

![old-vs-new-readme](https://cloud.githubusercontent.com/assets/138706/5326212/67d12bc4-7cbf-11e4-8fda-bf94cc428750.jpg)