message: Define 'audio_settings' in BasicGain_wApp
diff: //here are the libraries that we need
  #include <Tympan_Library.h> //include the Tympan Library
  +//set the sample rate and block size
  +const float sample_rate_Hz = 44100.0f ; //24000 or 44100 (or 44117, or other frequencies in the table in AudioOutputI2S_F32)
  +const int audio_block_samples = 32; //do not make bigger than AUDIO_BLOCK_SAMPLES from AudioStream.h (which is 128)
  +AudioSettings_F32 audio_settings(sample_rate_Hz, audio_block_samples);
  +
  //create audio library objects for handling the audio
  Tympan myTympan(TympanRev::E, audio_settings); //do TympanRev::D or TympanRev::E
  AudioInputI2S_F32 i2s_in; //Digital audio in *from* the Teensy Audio Board ADC.
  