message: updating step sequencer to Players instead of MultiPlayer
diff: </div>
  <script>
  //setup a polyphonic sampler
  - var keys = new Tone.MultiPlayer({
  - urls : {
  - "A" : "./audio/casio/A1.mp3",
  - "C#" : "./audio/casio/Cs2.mp3",
  - "E" : "./audio/casio/E2.mp3",
  - "F#" : "./audio/casio/Fs2.mp3",
  - },
  - volume : -10,
  - fadeOut : 0.1,
  + var keys = new Tone.Players({
  + "A" : "./audio/casio/A1.[mp3|ogg]",
  + "C#" : "./audio/casio/Cs2.[mp3|ogg]",
  + "E" : "./audio/casio/E2.[mp3|ogg]",
  + "F#" : "./audio/casio/Fs2.[mp3|ogg]",
  + }, {
  + "volume" : -10,
  + "fadeOut" : "64n",
  }).toMaster();
  //the notes
  if (column[i] === 1){
  //slightly randomized velocities
  var vel = Math.random() * 0.5 + 0.5;
  - keys.start(noteNames[i], time, 0, "32n", 0, vel);
  + keys.get(noteNames[i]).start(time, 0, "32n", 0, vel);
  }
  }
  }, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15], "16n");
  