Simplify the requestAnimationFrame backwards compatibility code

[fvsch]

For simplicity's sake, and since unprefixed rAF have been in the wild for a while, maybe simplify:

    // check what requestAnimationFrame to use, and if
    // it's not supported, use the onscroll event
    var loop = window.requestAnimationFrame ||
      window.webkitRequestAnimationFrame ||
      window.mozRequestAnimationFrame ||
      window.msRequestAnimationFrame ||
      window.oRequestAnimationFrame ||
function(callback){ setTimeout(callback, 1000 / 60); };

for:

    // check what requestAnimationFrame to use, and if
    // it's not supported, use the onscroll event
    var loop = window.requestAnimationFrame || function(callback){ setTimeout(callback, 16); };

Also it looks like the onscroll event is not used, so the comment should be fixed?

Browser support:
https://developer.mozilla.org/en-US/docs/Web/API/window/requestAnimationFrame#Browser_compatibility

• Firefox 23
• Chrome 24, Opera 15
• IE 10 (note that window.msRequestAnimationFrame never existed anyway)
• Safari 6.1

If support for Safari 6.0 is a goal, maybe keep only the webkit prefix.

[yairEO]

Note that it is best practice to write 1000 / 60 and not simply 16, which doesn't mean much by itself, and is also rounded...

This has been addressed in my fork of the project