message: terminate web worker on dispose
diff: @@ -435,28 +435,34 @@ define(["Tone/core/Tone", "Tone/core/Emitter", "Tone/core/Timeline"], function (
  return this._type;
  },
  set : function(type){
  - if (this._type === Ticker.Type.Worker){
  - this._worker.onmessage = null;
  - } else if (this._type === Ticker.Type.Timeout){
  - clearTimeout(this._timeout);
  - }
  + this._disposeClock();
  this._type = type;
  this._createClock();
  }
  });
  /**
  - * Clean up
  + * Clean up the current clock source
  * @private
  */
  - Ticker.prototype.dispose = function(){
  + Ticker.prototype._disposeClock = function(){
  if (this._timeout){
  clearTimeout(this._timeout);
  + this._timeout = null;
  }
  if (this._worker){
  + this._worker.terminate();
  this._worker.onmessage = null;
  this._worker = null;
  }
  + };
  +
  + /**
  + * Clean up
  + * @private
  + */
  + Ticker.prototype.dispose = function(){
  + this._disposeClock();
  this._callback = null;
  };
  