Create ES6-compatible modules

[adam-savard]

I've hacked together an ES6-compatible module for our own usage, but we should create releases for both Node JS and the browser.

Since this is dependent on PIXI, I'm not sure what the best approach to take is. We could pass in PIXI as a parameter to the plugin, but I think I'd rather investigate making this into a true, standalone plugin.

[adam-savard]

https://github.com/pixijs/plugin-boilerplate

This will prove useful! Requires porting to TS but that should be fine