Add modulation settings (don't yet affect audio output)
Refactor oscillator and modulator controls into Oscillator class
Modulator affects audio output (modulation amount currently all-or-nothing)
Modulation amount properly accounted for
Add modulation slewing functionality
Major refactoring; filter and envelope currently non-functioning
Waveforms are evaluated by native C functions using Ruby Inline
oscillator calls native C methods directly instead of going through Waveform object
Refactor frequency out of get_phase function signature
Remove sampling.rb, Inline-ify waveforms
Inline-ify sample method for oscillator and modulator
Implemented filter (with broken resonance control)