Decrease padding on num/denom header. 

This brings the column header closer to being centered over the actual text. I couldn't move the column itself since it was right up against the chart on the right. The two options I saw here were center over the actual num/denom or center over the num/denom and the icon.

![screen shot 2014-07-29 at 7 54 10 am](https://cloud.githubusercontent.com/assets/2308869/3734456/71ccd348-1717-11e4-84d5-e76b69e55bd7.png)

vs

![screen shot 2014-07-29 at 7 55 14 am](https://cloud.githubusercontent.com/assets/2308869/3734464/7959cf8a-1717-11e4-96fe-f1b86248be0f.png)

Option 1 is what I went with. If needed I can switch to option 2.