Minor: Prevent outline of UI buttons on focus

Before:
![screen shot 2013-10-23 at 10 39 09](https://f.cloud.github.com/assets/1655548/1388795/0975ec0c-3bc7-11e3-8e5d-ef8054a7f0bd.png)
![screen shot 2013-10-23 at 10 31 17](https://f.cloud.github.com/assets/1655548/1388761/898ee052-3bc6-11e3-8a93-b41f049de17d.png)

After:
![screen shot 2013-10-23 at 10 39 26](https://f.cloud.github.com/assets/1655548/1388798/0f405898-3bc7-11e3-964d-b85ee05c1b44.png)
![screen shot 2013-10-23 at 10 33 26](https://f.cloud.github.com/assets/1655548/1388764/8e73d6f4-3bc6-11e3-9e10-8341912b7896.png)