[threejs]: store animation frame ID on each request -- kill old animation frame when requesting a new one.
[threejs]: store animation frame ID on each request -- kill old animation frame when requesting a new one.

openconnectome/NeuroDataViz,neurodata/NeuroDataViz,openconnectome/NeuroDataViz,neurodata/NeuroDataViz,openconnectome/NeuroDataViz,neurodata/NeuroDataViz