Updates to 404 page as well as Grunt and Less

I noticed the same formatting issues from earlier on the 404 page. Then I went ahead and styled up a different 404 page (screenshots below) that attempts to search for the slug that the user typed in.

The ghost image is from the Ghost repository and is MIT.

![screenshot 2014-04-18 22 29 35](https://cloud.githubusercontent.com/assets/1126811/2747551/5afd87a0-c773-11e3-86b1-981bd0f66d36.png)
![screenshot 2014-04-18 22 29 38](https://cloud.githubusercontent.com/assets/1126811/2747552/5d5aacee-c773-11e3-8425-5acdad982387.png)