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.

![image](https://cloud.githubusercontent.com/assets/2308869/3734428/1611ec14-1717-11e4-8e40-04c654495883.png)

vs

![image](https://cloud.githubusercontent.com/assets/2308869/3734434/300f8004-1717-11e4-9841-a623260f442c.png)

Option 1 is what I went with. If needed I can switch to option 2.