Rewrite website to be suitable for blogging

Use the static website generator nanoc (http://nanoc.ws) to generate the
contents of the website. Doing this makes it possible to easily add more pages
to the website, such as blog posts, with a minimum of duplication and hassle.
Update `README.md` to reflect the fact that nanoc is now used.

Update `.gitignore`. Make git ignore files generated by nanoc.

Fiddle with existing website contents.

* Update the contents of the website landing page. Fiddle with prose and add a
  section which can link to blog posts.
* Slightly increase padding on the `<body>` element.
Add blog post discussing OpenVPN and split routing