[JS, SpineJS] Add rebind method for Spine's controller

spine.rebind.js

Spine.Controller.prototype.rebind = function(element) {
                var previous, _ref;
                _ref = [this.el, $(element.el || element)], previous = _ref[0], this.el = _ref[1];
                this.delegateEvents(this.events);
                this.refreshElements();
                return this.el;
            };