code: function SignalBinding(signal, listener, isOnce, listenerContext, priority) {
  
          /**
           * Handler function bound to the signal.
           * @type Function
           * @private
           */
          this._listener = listener;
  
          /**
           * If binding should be executed just once.
           * @type boolean
           * @private
           */
          this._isOnce = isOnce;
  
          /**
           * Context on which listener will be executed (object that should represent the `this` variable inside listener function).
           * @memberOf SignalBinding.prototype
           * @name context
           * @type Object|undefined|null
           */
          this.context = listenerContext;
  
          /**
           * Reference to Signal object that listener is currently bound to.
           * @type Signal
           * @private
           */
          this._signal = signal;
  
          /**
           * Listener priority
           * @type Number
           * @private
           */
          this._priority = priority || 0;
      }
docs: SignalBinding ------------------------------------------------- ================================================================ 
  Object that represents a binding between a Signal and a listener function.
  <br />- <strong>This is an internal constructor and shouldn't be called by regular users.</strong>
  <br />- inspired by Joa Ebert AS3 SignalBinding and Robert Penner's Slot classes.
  @author Miller Medeiros
  @constructor
  @internal
  @name SignalBinding
  @param {Signal} signal Reference to Signal object that listener is currently bound to.
  @param {Function} listener Handler function bound to the signal.
  @param {boolean} isOnce If binding should be executed just once.
  @param {Object} [listenerContext] Context on which listener will be executed (object that should represent the `this` variable inside listener function).
  @param {Number} [priority] The priority level of the event listener. (default = 0).