Jekyll 2 port

Fix #23

## Notes
- I don't think there's an easy way to tell if you're in development/production with Jekyll besides manually calling it with different command line options or config files. For now, the site will always be in the `production` environment.
- You'll need to figure out a way to host the site while using Jekyll 2 for the assets. You can host it on Heroku yourself (I've seen useful build packs and scripts for this), wait for GitHub pages to support Jekyll 2, or commit the outputted site to the repository and use Jekyll 2 on GitHub pages now.
- The 404 page is no longer using tempting because GitHub Pages requires 404 pages to be at `/404.html` and not use any Jekyll features.