Make prep_lab_file.py chop up audio

[erin-daphne-olson]

It would be super awesome if prep_lab_file.py could, in addition to making .lab files from TextGrids or .eaf files, also chop up the associated .wav file if there is more than one labeled interval on the tier.

[cesine]

I use one of mietta's praat scripts for this.. could that help :)