obj = CIntensityListener(iPlotAtEvery, hSpace, vRefractieIndex, caAmplitudeColors, fig)
  iPlotAtEvery - the plot will be updatet every iPlotAtEvery steps
  hSpace - 
  vRefractieIndex - refractive indices for consecutive envelopes in
    the current medium.
  caAmplitudeColors - cell array of line specifications for
    consecutive amplitudes (for example 3 amplitudes: {'r', 'g', 'b'}
  fig - id (number) of figure to use for plotting