requestAnimationFrame event emitter for browserify.
var raf =canvas = document
var raf =
var ee = raf([optional element], [optional tick function])
Returns an event emitter that immediately starts emitting 'data' events representing animation frames for a given element (or for the entire window, if no element is passed).
If you pass a function as the first or second argument it will get called on every tick. this is a convenience method for
the example above that binds to the
data event, e.g.
raf().on('data', tickFunction) is the same as
ee.pause() / ee.resume()
Pauses or resumes the events coming out of
dt on the next event after a resume will represent the difference between
the last rendered frame and the newest frame.