Promisify animation updates

[ryuuart]

This will take some figuring out, but everything should be updated before drawing. Especially for #34 .

[ryuuart]

I believe that everything does happen synchronously with updates since they're called in context of a loop, inside a render function, not inside a promise. What I believe should be happening is that each invocation of the functions during update() and draw() are adding execution stack frames across the board. If there are promises in these stack frames, they're still handled after execution of all these frames (in the microtask queue). So in other words, what I'm saying is that update() should be assumed synchronous until it doesn't show that behavior. After all, we update the entire system synchronously, so it's hard for me to imagine.