Tweak Atmosphere Sandcastle example
Tweak Atmosphere Sandcastle example

The Atmosphere Sandcastle disabled OIT for no reason. As we've learned in the past, this can lead to users copy and pasting it thinking they need it.
CesiumGS/cesium,CesiumGS/cesium,CesiumGS/cesium,CesiumGS/cesium,CesiumGS/cesium