Corrected Metro reading StaffObj clients. Factored MusicKit score and MIDI...

Commit by leighsmith :: r193 /trunk/Calliope/Application/ (35 files in 4 dirs): (link) Corrected Metro reading StaffObj clients. Factored MusicKit score and MIDI generation for file I/O. GVPerform will be replaced later. Moved saveEPS & saveTIFF to OpusDocument. Replaced VOICEID macro with -voiceWithDefault: method. Added extra copyWithZone methods to Staff, newFrom in Graphic and subclasses defaults to calling copyWithZone:. Added partName accessors. Font debugging turned back on while I try to nail this down. Inverts Verse fonts if negative when encoded.