Fix loadTile
Fix loadTile

likangning93/cesium,geoscan/cesium,josh-bernstein/cesium,jasonbeverage/cesium,YonatanKra/cesium,progsung/cesium,CesiumGS/cesium,likangning93/cesium,YonatanKra/cesium,progsung/cesium,CesiumGS/cesium,YonatanKra/cesium,likangning93/cesium,CesiumGS/cesium,AnalyticalGraphicsInc/cesium,AnalyticalGraphicsInc/cesium,CesiumGS/cesium,likangning93/cesium,CesiumGS/cesium,YonatanKra/cesium,likangning93/cesium,geoscan/cesium,josh-bernstein/cesium,jasonbeverage/cesium