* bus/connection.c: implement pending reply tracking using
	BusExpireList

	* bus/bus.c (bus_context_check_security_policy): verify that a
	reply is pending in order to allow a reply to be sent. Deny
	messages of unknown type.

	* bus/dbus-daemon-1.1.in: update to mention new resource limits

	* bus/bus.c (bus_context_get_max_replies_per_connection): new
	(bus_context_get_reply_timeout): new