Fix NaN faces and vertices with latest three.js

[benjaminleonard]

As per: https://github.com/aframevr/aframe/pull/3616

Also switching some deprecated parts so the example works with three.js r93 There seems to be a slight issue with the way the sprites render on the new version – not sure if you know why that is?

Vertices have been removed since they're no longer provided by three.js.