Swing indications using system text

[fkretlow]

@jbegin

This is really impressive! Too bad about the Mac bug. Any kind of metric modulation with a single tuplet note (ex. s=7s) doesn’t work on the Mac. Bummer!

I can’t do this for every possible combination, but if you tell me which modulations you need I can add pre-built composites for them so they work on Mac.