code: function sortPitches (pitches) {
    return pitches.map(Pitch).sort(function (a, b) {
      return a - b
    }).map(function (pitch) {
      return pitch.sciPitch()
    })
  }
docs: helper function to sort an array of pitches from lowest to highest
  @param {string[]} pitches - an array of pitch strings
  @returns {string[]} a new clone of the provided pitch string
  array sorted from low pitch to high pitch