Feature request: ability to cache downloaded scenes in ThreeJS cache

[AlexRynas]

It would be nice to be able to enable caching of scenes loaded with addSplatScene or addSplatScenes using both regular and progressive loading. Ideally, the splatBuffer would be cached so that when the addSplatScene or addSplatScenes function is called again, the cached splatBuffer would be parsed into the splatMesh again.

[mkkellogg]

Sorry for the delayed response, this should be a pretty straightforward thing to add so I'll try to get it into a release soon.