Case config

This is a big, mostly UI, PR changing all of the Case Config UI to adopt the direction started by the Child Case (subcases) UI.

This includes a backend feature as well: creating subcases from a repeat question.

The "Requires a..." section was replaced with form types:
- doesn't use cases at all
- registers a case
- updates a case
- registers a case for other modules

Instead of one checkbox per xml "action" (create, update, close), the new UI shows create & update together similarly to how child cases were.

The inputs and selects were also made to be searchable/auto-completing; in particular, the case property box suggests cases that have already been used in that form or other forms with the same `case_type`.
![screen shot 2013-06-17 at 5 56 15 pm](https://f.cloud.github.com/assets/137212/665277/f02e5bfe-d798-11e2-8593-6fdf281b4b14.png)