Use study status properly

This blocks the attachment of raw data to the study until after the study metadata is approved. It also adds two buttons for admins to approve a study and to make a study public.

This finishes #476 
Remove the `<br />`, it appears on the string:

![screen shot 2014-11-19 at 11 51 25 am](https://cloud.githubusercontent.com/assets/2501478/5112088/71cf7c3c-6fe2-11e4-9879-b7b488b69ebd.png)