Make "My Uploads" look disabled when not logged in

- When not logged in, it goes gray and has a tooltip "Log in to enable"
- When clicked anyway, repaired the function of displaying the "Please log in" dialog
- Possible 'to do': logging out does not clear the filter.
Merge pull request #123 from JohnThomson/feature/myUploadsRequiresLogin

Make "My Uploads" look disabled when not logged in