Neume

Copperbox revision 1258.

I've removed the Extra.Extended module that was inherited from Mullein with a module solely for Tab notes - i.e. notes with string number annotations.

Extra.Extended was quite grisly as it served rather different purposes in Mullein. I expect that for Neume each extended note type - i.e. notes with string annos, fret diagrams - will have its own module and 'annotation' types rather than trying to share common types (which was the model Extra.Extended was following).

Extended glyphs will share the common primitive glyph types of course, Glyph (for notes, chords, graces...) or MarkupGlyph (for Fret diagrams etc).