Include exception code and, if applicable, error constant.

This resolves Issue #65 by including the exception code or error constant after the exception name in PrettyPageHandler.
![screenshot from 2014-05-22 08 31 35](https://cloud.githubusercontent.com/assets/44527/3054284/f7af423a-e1b5-11e3-8a2a-2465ed2408b1.png)