neume-core

Copperbox revision 1430.

The B6 example now produces valid output. There are a lot of convenience functions missing from neume-core (compared to the original Neume), so the B6 example has to do quite a bit with the wl-pprint combinators directly to produce valid scores. However, I'm not going to add the missing functions to neume-core; instead I'll make a neume-extra package for them.

Putting the extra functionality into a new package, means I should actually be able to "finish" neume-core this time. Reworking the bracket functionality is the main thing left to do.