message: test if waveshaper shim is already installed
diff: define(["../core/Tone", "../shim/AudioContext"], function(Tone){
  - if (Tone.supported){
  + if (Tone.supported && !Tone.global.AudioContext.prototype._native_createWaveShaper){
  //fixes safari only bug which is still present in 11
  var ua = navigator.userAgent.toLowerCase();
  