better raf polyfill suggestion
Just iter twice through scene to test obj collisions.
Remove fns no longer needed because of new collision test approach.
Date.now() is not supported by all browsers.

https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Date/now
Make lastUpdatedAt a local var.
Make ball responsible for setting its own velocity and initial position.
Make boardWidth and boardHeight into constants.
Fuck it just use the raf shim.
Make Inputter obj to handle keyboard input.
Feels like collision should be done before and outside update.