added has parent element, make sure get/has children/parent query is run only once by object.
added has parent element, make sure get/has children/parent query is run
only once by object.
luyadev/luya,vuongminh/luya,nandes2062/luya,martinpetrasch/luya,luyadev/luya,nandes2062/luya,nandes2062/luya,martinpetrasch/luya,zephir/luya,zephir/luya,nandes2062/luya,vuongminh/luya,martinpetrasch/luya,vuongminh/luya,zephir/luya,zephir/luya,martinpetrasch/luya,zephir/luya,luyadev/luya,vuongminh/luya