CSS Modification for Light Themed Pinned Queries

This closes Issue 667 (https://github.com/elasticsearch/kibana/issues/667) by adding a line of light theme specific css to a pinned label. 

![screen shot 2013-12-08 at 1 24 18 pm](https://f.cloud.github.com/assets/246603/1701192/cffaa7fc-6046-11e3-879d-1427f6159882.png)
![screen shot 2013-12-08 at 1 23 12 pm](https://f.cloud.github.com/assets/246603/1701193/cffc4e22-6046-11e3-98ce-f0280a23fa80.png)