v0.6.0

This release contains breaking changes, i.e., changes that can affect how patches sound.

Changed

• When triggering note while envelope is still running, restart envelope from
  zero volume
• To prevent artefacts, for very short envelope stages, the normal logarithmic
  slopes will be mixed with linear slopes. This is now done for slightly longer
  envelope stages
• Adjust LFO wave shapes for better beat fit
• Interpolate parameters for 32 samples

Fixed

• Properly handle audio buffers of arbitrary size
• Properly handle midi event timings
• Fix LFO retrigger issues
• Properly treat MIDI note on/off event with 0 velocity as note off