HNotate

Copperbox revision 326.

I've made a separate module for the 'fitting' functions and typeclass, and added a very general sectioning function that can split sequences into measured lengths and optionally hyphenate them when an element has been split across two sections (for music this would mean putting a tie at the end of the left bar).

I haven't yet replaced partitionGVO the HNotate function that currently does bar division with a complex stateful fold, but once I do, I should be able to handle notes with duration greater than the bar length. Currently HNotate's behaviour for extra long notes is unknown.