Adding spectrogram to "Simpler" Processing GUI.

Added a spectrogram to the "simpler" processing GUI.  I added a button
to allow the user to toggle between the time-domain montage plot and the
spectrogram.
Has Alpha Detection and Spectrogram.
Merge pull request #2 from chipaudette/master

Update "Simpler" Processing GUI.  Adds spectrogram and alpha detection.