Update paginator padding to vertically-center text

This might not be the best way to fix this, but since `vertical-align: middle;` didn’t work, I put in exact pixel values in the padding.

**Before**
![paginator-before](https://f.cloud.github.com/assets/293844/1916431/738a2048-7d78-11e3-91e3-761113809aa6.png)

**After**
![paginator-after](https://f.cloud.github.com/assets/293844/1916432/779e8246-7d78-11e3-9939-5274b03a3d8e.png)