* bus/signals.c (bus_signals_test): add match_rule_equal() tests
	(match_rule_matches): remove unused arg
	(test_matching): add tests for match_rule_matches()

	* bus/signals.c (bus_match_rule_parse_arg_match): add ability to
	do arg0='foo' arg5='bar' in the match rules
	(match_rule_matches): don't match if the arg0='foo' doesn't match.

	* dbus/dbus-protocol.h (DBUS_MAXIMUM_MATCH_RULE_ARG_NUMBER): add this