Adds consent and registration status counts to Class roster page

All page viewers can see the registration status counts, but only researchers and admins can see the consent status counts.

There is a lot of formatting left to do on this page.

![Screen Shot 2013-04-02 at 4 09 41 PM](https://f.cloud.github.com/assets/1851667/331384/7009b958-9bea-11e2-8fe2-a17325128dac.png)