Started adding rest support. Bit of cleanup.
Use ValueError rather than generic exception
Add checking for range of notes, so I don't blow out my eardrums and ruin my 00 headphones
Move sample rate to end of parameters, so it's easier to leave at the default
Never again, will I try to send nonprintable chars through a pipe. Tried to pipe a struct containing the integerr 13 (carriage return), which shows up on the other side of the pipe as 10. Very difficult to find. This hack came with a price.
Yay, RESTs now work! Use 'z' in an ABC string.