Add postRender and preRender to Cesium extern
Add postRender and preRender to Cesium extern

gberaudo/ol3-cesium,thhomas/ol3-cesium,openlayers/ol-cesium,openlayers/ol3-cesium,openlayers/ol3-cesium,openlayers/ol-cesium,gberaudo/ol3-cesium,oterral/ol3-cesium,oterral/ol3-cesium,thhomas/ol3-cesium,thhomas/ol3-cesium