Fix group list expansion styling on profile page

I copied the style of the other rows to fix a whitespace problem, and fixed a bug in the pluralization filter.

Before:

![screen shot 2014-12-30 at 2 48 40 pm](https://cloud.githubusercontent.com/assets/17363/5583271/04f0cdc0-9033-11e4-8a12-ff89d9889d2e.png)

After:

![screen shot 2014-12-30 at 2 48 05 pm](https://cloud.githubusercontent.com/assets/17363/5583274/0d3d0bb0-9033-11e4-9058-765f6460d01c.png)

This is the last bit of styling to implement for #158