Iron Out User Display Name

[curran]

The current state of displaying user names is rather despicable.

The username is shown in the profile page and in visualization page, while the full name is displayed in the login widget (top right). If the full name is not defined, the login widget is an empty box.

For all three of these cases, the best "display name" available should be displayed. Namely:

• If the full name is available, display it.
• Otherwise, display the username.