function getRequestAnimationFrame () {
		var lastTime = 0;
		var vendors = ['ms', 'moz', 'webkit', 'o'];

		for (var x = 0; x < vendors.length; x++) {
			if (window[vendors[x] + 'RequestAnimationFrame']) { return window[vendors[x] + 'RequestAnimationFrame']; }
		}

		return function (callback) {
			var currTime = new Date().getTime();
			var timeToCall = Math.max(0, 16 - (currTime - lastTime));
			var id = window.setTimeout(function () {
				callback(currTime + timeToCall);
			}, timeToCall);
			lastTime = currTime + timeToCall;
			return id;
		};
	}
gets a prefixed rAF version or a polyfill to use if window.requestAnimationFrame is not available
@returns {Function}