3.0.0 - Swift 4

Swift 4 migration.

2.0.1 - Fix warnings

Fix warnings

2.0.0 - Swift 3

Swift 3 conversion #21 by @glaurent

1.0.0 - Pitchy

Initial release:

• Get lower, higher and closest pitch offsets from a specified frequency.
• Get an acoustic wave with wavelength, period and harmonics.
• Create a note from a pitch index, frequency or a letter with octave number.
• Calculate a frequency, note letter and octave from a pitch index
• Find a pitch index from a specified frequency or a note letter with octave.
• Convert a frequency to wavelength and vice versa.
• Convert a wavelength to time period and vice versa.