o Don't show technical info such as frequency and audio level.
o Show final successful note in green as well.
o Practice: make pitch detection octave agnostic (the algorithm we use
  to detect pitch is not good at that)
o Provide an Note.Annotator that can add its own annotations.
o Implement an annotator that highlights the current note and
  displays the amount of time 'in-tune'
o Make it not a penalty if no data arrives.
o cent-view was disabled if detection was off by an octave.