Add support for time value syntax

[tmhglnd]

Would be nice to have support for the more widely used Time Value Syntax (like in Ableton and Max/MSP) like: 1n 4n 8nt 16nd etc.

Tone.js uses a bit different time syntax, this could also be supported since it allows for values in measures: 1m 3m 4n 8t 16n.