Decrease padding on num/denom header. This brings the column header closer to being centered over the actual text.
Merge pull request #227 from pophealth/centerFractionColumn

Decrease padding on num/denom header.

I think there might be a better way to do this (as a column or thereabouts), as changing the size of the icons or the size of the num/denom text would require a change to this again. But we can make that change later.