* dbus/dbus-auth.c (sha1_handle_second_client_response)
	(handle_server_data_anonymous_mech): add the process ID from
	socket credentials, if available, even if not using EXTERNAL

	* dbus/dbus-transport.c (auth_via_default_rules): support
	allow_anonymous flag

	* dbus/dbus-connection.c (dbus_connection_get_is_anonymous)
	(dbus_connection_set_allow_anonymous): new API for controlling
	anonymous access