Neume

Copperbox revision 1195.

Preliminary work on fret diagrams in LilyPond output. Fret diagrams are due to be rendered as markup syntax - i.e. invisible spaces with above the staff markup annotations. This uses a simpler 'syntax' than standard staff notation - no graces, chords or beam groups - but quite a lot of the code to work with the simpler syntax is missing (e.g. bar splitting).