Potential bug when session changes state

[RiJo]

In the file spotlight/service/session/SpotifyCallbacks.py the following callback function is defined:

    def connectionstate_updated(self, session):
        self.authenticator.logged_in()

According to some documentation I found (ref) the callback could (also) be called when the session went offline: "Called when the connection state has updated - such as when logging in, going offline, etc."

Some additional checks are (probably) required in the implementation to properly handle all scenarios.