Handle disabled internet (and provide a message to the user if he
tries to login with internet disabled).
Added error sfx.
Added 'ok' button to 'new player' dialog. I can't seem to get them next
to each other, so for now they are just on top of each other.
Block new StoryModeLobbyScreen while login is in progress (and display ...
while this is happening). This allows to show error messages (e.g. user can
re-enter the password if login failed, without having to go to another menu
or perhaps even missing the fact that they are not logged in).