Removes empty buttons when no actions have been defined

Before:
![feeds - sonatype nexus 2014-12-17 14-07-01](https://cloud.githubusercontent.com/assets/186715/5479855/0c7f9180-85f6-11e4-99de-34f27c46d4a4.png)

After:
![feeds - sonatype nexus 2014-12-17 14-06-29](https://cloud.githubusercontent.com/assets/186715/5479860/0ff1f74a-85f6-11e4-83e3-d0a7c473cf26.png)