waveform.py: add a random phase shift to the Generator class
waveform.py: add a random phase shift to the Generator class

When mixing multiple signals together, if they all have the same phase,
then there will be more {con|de}structive interference. Adding a random
phase shift into each new note reduces the interference a wee bit.

fretboardfreak/potty_oh,fretboardfreak/potty_oh