Mullein and Bala

Copperbox revision 818.

Improvements to annotations in Mullein. For Mullein, annotations now seem to be adequate - following the examples in the module Extended its simple enough to create and render new annotations. Annotations don't place much burden on other code - I've got rid of a the MakeNote typeclass that was a burden previously.

Annotations in Bala are still unsatisfactory - I've added temporary functionality (distAnnos) to annotate notes after they have been assembled into tunes, but really I need a comfortable means* to annotate whilst I construct tunes.

* i.e. some means that lets me separate pitch content from string numbers at least til I want to zip them.