MATLAB script for generating spectrograms

This script generates auditory spectrograms for all files in the TIMIT
corpus.  I uses (1) the readsph function from the Voicebox toolbox for
reading in TIMIT WAV (sphere) files, (2) the wav2aud function from the
NSL Toolbox to generate spectrograms, and (3) the getfiles function
from the Mathworks File Exchange to read in all WAV file names from the
TIMIT directory structure.