title: AudioContext not allowed to start in ToneJS (Chrome)
body: <p>Using ToneJS in Chrome, I frequently get this error message: "The AudioContext was not allowed to start. It must be resume (or created) after a user gesture on the page."</p>
  
  <p>For example, with the code below, I get this message every time I use ctrl-r or ctrl-f5 to refresh the page.</p>
  
  <p>I can get it working again by typing <code>Tone.context.resume()</code> into the console, but that gets pretty repetitive. Why this is going on, and how can I stop it?</p>
  
  <pre><code>var keyToPitch = { "z":"C3", "s":"C#3", "x":"D3", "d":"D#3", "c":"E3", "v":"F3", "g":"F#3", "b":"G3", "h":"G#3", "n":"A3", "j":"A#3", "m":"B3", ",":"C4" }
  
  
  var synth = new Tone.PolySynth(6, Tone.Synth, {
      "oscillator" : {
          "type": "sawtooth",
          "partials" : [0, 2, 3, 4],
          }
      }).toMaster();
  
  
   window.addEventListener('keydown', this.onkeydown)
   window.addEventListener('keyup', this.onkeyup)
  
  function onkeydown(e){
     synth.triggerAttack(keyToPitch[e.key], Tone.context.currentTime)
  }
  function onkeyup(e){
      synth.triggerRelease(keyToPitch[e.key])
  }
  </code></pre>