feature request: macOS support

[xyproto]

I created a pull request for carlmjohnson/pomodoro, which uses beep.

The pull request was rejected because beep does not support macOS.

Please add support for macOS.

[xyproto]

And thanks for creating beep! I had a lot of fun making a very short tune.

[dbatbold]

Sorry for the trouble. I'll look into porting the project to macOS when I have time. Thanks!

[xyproto]

No trouble, and nothing to apologize. Beep is your project, and it's pretty cool as it is. No rush. Appreciate it!