Put space between icon and text in multimedia button groups

This looks bad:
![before](https://cloud.githubusercontent.com/assets/1486591/5144469/aac58464-7168-11e4-876f-e7714fa41e0c.png)

This is better:
![after](https://cloud.githubusercontent.com/assets/1486591/5144476/b2eeb5c0-7168-11e4-88c4-8f8ddb46c8c0.png)