ia.css: increase padding around the "Clear" filter.

Before:
![screen shot 2014-12-16 at 11 12 19 am](https://cloud.githubusercontent.com/assets/81969/5456837/772cde6c-8514-11e4-9a58-6e699094511a.png)

After:
![screen shot 2014-12-16 at 11 12 08 am](https://cloud.githubusercontent.com/assets/81969/5456840/8002a260-8514-11e4-93e8-89b896ac7062.png)