If we know ahead of time which entities will have components on
them or a template attached to them, then we can identify scene
graph subtrees which can act as leaves of the entity tree and
refrain from inflating extra entities underneath them.

caching for gifs

to get content type

zone

The PolyfillControls helper has some breakage where it doesn't
always use the polyfilled VRFrameData class. Also, we don't even
want the pose data to be applied to an Object3D, so it seems a
little bit silly to use.