Improve aesthetic of stars on ratings button

r? @ngoke

![screen shot 2014-07-15 at 3 23 36 pm](https://cloud.githubusercontent.com/assets/23885/3590920/41fe03c6-0c5e-11e4-8108-b18ebaa1ca73.png)

Possibly not needed, but I'm not familiar enough with Fireplace CSS to not include this extra bit of specificity.