Replace const and let with var for es5
Replace const and let with var for es5

likangning93/cesium,likangning93/cesium,CesiumGS/cesium,YonatanKra/cesium,AnalyticalGraphicsInc/cesium,CesiumGS/cesium,likangning93/cesium,CesiumGS/cesium,YonatanKra/cesium,progsung/cesium,CesiumGS/cesium,CesiumGS/cesium,AnalyticalGraphicsInc/cesium,YonatanKra/cesium,likangning93/cesium,likangning93/cesium,progsung/cesium,YonatanKra/cesium