code: function setPoint(timeStamp, identifier) {
      if (identifier === undefined || identifier === null || identifier.length === 0) {
        identifier = "default";
      }
  
      this.points[identifier] = new WaveformDataPoint(this, timeStamp);
  
      return this.points[identifier];
    }
docs: Creates a new point of data.
  Pretty handy if you need to bookmark a specific point and display it
  according to the current offset.
  
  ```javascript
  var waveform = WaveformData.create({ ... });
  
  console.log(Object.keys(waveform.points)); // -> []
  
  waveform.set_point(10);
  waveform.set_point(30, "speakerA");
  
  console.log(Object.keys(waveform.points)); // -> ['default', 'speakerA']
  ```
  
  @param {Integer} timeStamp the time to place the bookmark
  @param {String*} identifier Unique identifier. If nothing is specified,
  *default* will be used as a value.
  @return {WaveformDataPoint}