and msg arguments.
(isc_tcp_destroy_fn): Function removed.
(isc_connecttcp): Ditto.
(isc_opentcp): Ditto.
(isc_tcp_funs): Function table removed.
(isc_createtcp): Added mcb and initial_state arguments.  Removed
	obsolete bogus setsockopt() calls.
(isc_bindtcp): Don't check the type of the session.
(isc_accept_cb): New function.
(isc_listentcp): Added the cb argument.  Don't set the state here;
	that is now done by isc_create().  Add isc_accept_cb() as a
	read callback.