Added sign out link when hovering over name (fixes #352)

When hovering over the players name in the sidebar a sign out link will appear.

![image](https://f.cloud.github.com/assets/198225/208212/2054be30-8218-11e2-9bcd-4d9ee1c7e850.png)

Tested in Firefox 19.0.1 and Chome 26.0.1410.19