Fix point primitives behind the camera appearing in front of it.
Fix point primitives behind the camera appearing in front of it.

AnalyticalGraphicsInc/cesium,YonatanKra/cesium,YonatanKra/cesium,kaktus40/cesium,likangning93/cesium,soceur/cesium,geoscan/cesium,josh-bernstein/cesium,YonatanKra/cesium,kaktus40/cesium,soceur/cesium,likangning93/cesium,likangning93/cesium,likangning93/cesium,CesiumGS/cesium,soceur/cesium,CesiumGS/cesium,progsung/cesium,hodbauer/cesium,AnalyticalGraphicsInc/cesium,hodbauer/cesium,josh-bernstein/cesium,YonatanKra/cesium,hodbauer/cesium,CesiumGS/cesium,jasonbeverage/cesium,progsung/cesium,CesiumGS/cesium,CesiumGS/cesium,likangning93/cesium,geoscan/cesium,jasonbeverage/cesium