Question pane cleanup

Goals:
- simplify UI and order things logically
- make vellum fit in with the look and feel of the rest of HQ
- clean up UI

![screen shot 2013-07-24 at 11 29 45 am](https://f.cloud.github.com/assets/716573/846814/54291b2c-f426-11e2-9a9f-1dfec87a496c.png)

Related Pull Requests:
https://github.com/dimagi/commcare-hq/pull/730
https://github.com/dimagi/hqstyle-src/pull/42