updated changes.md
updated changes.md

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