add threejs + wasm worker + gltf model

[albjeremias]

To help out! :) my cents on this one: #28 (comment)

I'd rather refactor all this example code, the code should be a bit more readable.

It also affects: artoolkitx#98 the framerate won't drop that badly (when the conainer size is not resized, so it stays fullscreen) but it won't solve it.

[albjeremias]

anyway.. would it be possible to write this examples more in this style why aren't this examples written like that? what are the missing pieces?

[kalwalt]

,@albjeremias rigth now i'm out of my PC and i have not to time to look at this, i hope next week to review your code. Anyway i thank you for your time spent on this! 🙂

[albjeremias]

did you check out https://developer.mozilla.org/en-US/docs/Web/API/SharedWorker ? I'm thinking of using this to create an example more on the style i mentioned.

[kalwalt]

See here #2