* dbus/dbus-message.c (_dbus_message_test): enable and fix the
	tests for set_path, set_interface, set_member, etc.

	* dbus/dbus-string.c (_dbus_string_insert_bytes): allow 0 bytes

	* dbus/dbus-message.c (set_string_field): always just delete and
	re-append the field; accept NULL for deletion
	(re_align_fields_recurse): reimplement