message: close always returns a Promise
diff: @@ -9,10 +9,9 @@ define(["Tone/core/Tone", "Tone/shim/OfflineAudioContext"], function(Tone){
  if (!AudioContext.prototype.close){
  AudioContext.prototype.close = function(){
  if (Tone.isFunction(this.suspend)) {
  - return this.suspend();
  - } else {
  - return Promise.resolve();
  + this.suspend();
  }
  + return Promise.resolve();
  };
  }
  