Search for possible pages on 404

Based on [an article](http://brettterpstra.com/2013/04/07/fun-with-intelligent-404-pages/) the idea came to search the website for possible matches on a 404 page.

The result:

![Schermafbeelding 2013-04-08 om 16 58 53](https://f.cloud.github.com/assets/1014380/352124/e690d48c-a05c-11e2-8920-78c91b5804ec.png)

Feedback welcome on both the idea as the implementation.