Callback functions

[shshaw]

The ability to have a complete callback when the animation is done would be quite handy. start could also be useful.

var flip = new FLIP({
  element: target,
  easing: function (t) {
    return t * t;
  },
  start: function(){ console.log('animating is starting'); },
  complete: function(){ console.log('animation is done!'); }
});