dbus-viewer introspected and displayed the bus driver

	* dbus/dbus-object-tree.c
	(object_tree_test_iteration): add tests for a handler registered on "/"

	* dbus/dbus-object-tree.c
	(_dbus_decompose_path): fix to handle path "/" properly
	(run_decompose_tests): add tests for path decomposition

	* glib/dbus-gutils.c (_dbus_gutils_split_path): fix to handle "/"
	properly

	* glib/dbus-gobject.c (handle_introspect): fix quotes

	* test/glib/run-test.sh: support launching the bus, then running
	dbus-viewer

	* test/glib/test-service-glib.c (main): put in a trivial gobject
	subclass and register it on the connection

	* bus/driver.c (bus_driver_handle_introspect): implement
	introspection of the bus driver service

	* dbus/dbus-protocol.h: add #defines for the XML namespace,
	identifiers, doctype decl

	* bus/driver.c (bus_driver_handle_get_service_owner): handle
	attempts to get owner of DBUS_SERVICE_ORG_FREEDESKTOP_DBUS by
	returning the service unchanged.
	(bus_driver_handle_message): remove old check for reply_serial in
	method calls, now the message type deals with that
	(bus_driver_handle_message): handle NULL interface

	* glib/dbus-gproxy.c (dbus_g_proxy_get_bus_name): new function

	* glib/dbus-gloader-expat.c (description_load_from_string): allow
	-1 for len

	* tools/dbus-viewer.c: add support for introspecting a service on
	a bus

	* glib/dbus-gproxy.c (dbus_g_pending_call_ref): add
	(dbus_g_pending_call_unref): add