added some comments
streamlined test code
making different test files
stft unit test
fixed half the stft tests
STFT tests now pass.

Two gotchas here:
    1- I had to switch stft.m to use matlab's built in hann() function
    2- STFT test passes if either D or D.conj() matches matlab.

Not sure what's going on here yet.
fixed a bug in istft
istft tests pass when using matlab's hann()
fixed a bug in melfb test generator: 180 fails now
melfb tests pass.
added documentation to core test suite
rearranged core library a bit
flattened ft in istft: much cleaner now
removed deprecated code