All custom admin

Functionally replace Django's built in admin with our own custom interfaces.

A summary of the major changes:
* New 'admin' app that contains all the custom admin logic
* Move to wysihtml5 instead of wymeditor
* Updated citeproc-js (1.0.409), jquery (1.8.2), and jquery-ui (1.8.24)

There's some cleaning up and refactoring to be done, but everything is operational.

*There Will Be Bugs*