Replace Time.every with AnimationFrame

[rl-king]

Use browser's native render hook. As described at http://package.elm-lang.org/packages/elm-lang/core/5.1.1/Time#every Time.every is not the ideal way to achieve smooth animations. The AnimationFrame package provides a hook to the browser's requestAnimationFrame function.

[furrary]

When I read the docs, I thought that I need JS Interop to achieve this. Thanks for the PR.

[rl-king]

Ah yea, I can see why, it's not very clear from those docs.