neume-core

Copperbox revision 1433.

I've added code to beam or not a metrical pulse. I'd forgotten how complicated this is - e.g. accounting for beams cannot start or end on rests. The new function dividePulse is quite clean though it needs a lot of machinery - trace monad, a special buffer data structure...

It also needs some cleaning up from its current state, before it moves into Core.Bracket from Temp01.hs.