AnalyticalGraphicsInc/cesium — pull request #657 by mramato (2013-04-19 15:19:22+00:00)
Title: ReferenceProperty availability

Make ReferenceProperty have the same availability as the DyanmicObject that the reference is on. This addresses an issue @mrmattf while attempting to draw a line between two DynamicObjects, one of which becomes unavailable over time.