Use Whoops for local debug output

Provides much the same functionality as the old error handler, but in a much cleaner and easier to understand manner.

### Old

![screen shot 2014-07-23 at 17 21 12](https://cloud.githubusercontent.com/assets/619082/3676185/91d52bb8-1285-11e4-9bda-0c1c16b553bb.png)

### New

![screen shot 2014-07-23 at 17 21 46](https://cloud.githubusercontent.com/assets/619082/3676188/939e4042-1285-11e4-9538-363aad3fbf9e.png)