Added backend and frontend JS to render the site pages.

- Server responds with either a full html page or just the content requested depending on whether it gets an AJAX request or not.
- This means search crawlers, people on legacy devices, or just people who hate JS can still use the site with no problem
- People who have JS enabled can navigate via AJAX (very fast, won't reload entire page everytime you go somewhere)
- Big thanks to Andrew Theken: http://stackoverflow.com/questions/11041168/nodejs-jade-conditional-extend
- MIGHT affect performance, I'm not sure if Express will still cache the pages.