Fix input box border

For some reason the top-left and bottom-left corners of the first input field are not rounded.

![screen shot 2014-12-15 at 09 20 15](https://cloud.githubusercontent.com/assets/2194396/5433084/a8bf0880-843b-11e4-88ab-ba798117d726.png)

Looks good to me, but will also need this in the student UI.