message: Examples: update header comments
diff: filters in the frequency-domain, whereas I implemented them in the time-domain.
  I've also added an expansion stage to manage noise at very low SPL
  - Uses Teensy Audio Adapter ro the Tympan Audio Board
  - For Teensy Audio Board, assumes microphones (or whatever) are attached to the
  - For Tympan Audio Board, can use on board mics or external mic
  + Uses Teensy Audio Adapter.
  User Controls:
  Potentiometer on Tympan controls the algorithm gain
  