Userlist top is 1px off

Top shows existing behaviour, bottom shows new.  Ridiculously minor OCD-level change.

![jabbr-users-top](https://f.cloud.github.com/assets/1271535/319118/193efcfe-98b2-11e2-9244-2de4e88b517b.png)

This also clarifies the messages UL's margins (overriding [somewhat arbitrary padding] inherited from bootstrap's ul class)