Examples always run off the local copy instead of the installed gem (easier to work with)
Basic implementation of phase modulation

Basic implementation of phase modulation (the Yamaha DX7 called it
"frequency modulation".) What doesn't work cleanly is changing the
ratio of the modulator on the fly (this causes "pop" sounds.) That's
probably fixable but beyond me right now.
Ignore wav files output in the examples dir
Removing test.wav from the example dir
Additive synthesis

Overtone logic already existed in Instrument. I moved this out into an
OvertoneAdder class and extracted the generic "add some waveforms"
notion into an Adder class so you can add whatever waveforms you want.
Rubification and a minor bug fix

Changing camelCase keywords to ruby_style. Changed some iterators to be
more Ruby-like, fixing a bug along the way (next_samples returned the
first sample at the end of the array instead of the start)