ia.css: widen the list of IAs a little.

Widen the IA list a little, and make the filters a little narrower:

Before:
![screen shot 2014-12-16 at 11 18 19 am](https://cloud.githubusercontent.com/assets/81969/5456961/57fb6c88-8515-11e4-929f-8cdc2fd483f5.png)

After:
![screen shot 2014-12-16 at 11 18 09 am](https://cloud.githubusercontent.com/assets/81969/5456962/5bd82ee0-8515-11e4-873f-cc57cd5330a6.png)