adding event handler and default login/connect UI

- Adding div at the top left corner to show basic user profile info
(photo, UID, name)

- Adding global event handlers for
onLogin/onLogout/onConnectionAdded/onConnectionRemoved that will render
the basic user profile info the top.

- Adding loginUI and addConnectionUI that are alwayes rendered for easy
access
fix bug in showUserInfo method

Fixing a bug where if the user in undefined, we still try to read it's
UID property.
Adding new commands

adding Get Friends and Logout commands to the commands list