Filter MUC 'decline' messages by type 'normal'
and not by '!error' as this there are presence stanzas containing the
muc#user namespace also send to the client, which results in a
ClassCastException in the StanzaListener.
Move TLS Required check at the end of connect()
It was a *very* bad idea to perform the SecurityMode.Required check in
the connection's reader thread and not at the end of
AbstractXMPPConnectin's connect(). :/
This behavior dates back to 8e750912a765f77a4f178a4f307a8b42c2afb5ae
