Update CHANGES.md.
Update CHANGES.md.

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