b69e92c992
validate roots because when their children are invalidated, it causes the entire hierarchy to be invalidated, which we then must revalidate lest they live the rest of their mortal lives as invalids. git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@1900 542714f4-19e9-0310-aa3c-eee0fc999fb1