Added an error page

It's not so pretty, but its a start. @AlexeyMK @yefim feel free to improve on it, but I don't have time tonight to fiddle with it much more.

![screen shot 2013-12-04 at 4 34 47 pm](https://f.cloud.github.com/assets/1057528/1677684/fd787682-5d2b-11e3-8701-f34b61807383.png)