Use the ACE code editor

Couple minor fixes, but the real goal was to add the ACE edtior -- http://ace.c9.io/#nav=about. There was a cool demo at @code4lib that had a contextual MODS editor that I want to play with at some point.

![screen shot 2014-04-01 at 13 45 37](https://cloud.githubusercontent.com/assets/111218/2584435/a7e144f0-b9de-11e3-902c-169fc68113d2.png)