Returns a FoscOctave.
Octave
[ ]
FIXME: make examples which don’t use gui
inspect(FoscOctave(7));
inspect(FoscOctave("A-1"));
inspect(FoscOctave("cs''"));
inspect(FoscOctave("A")); // octaveNumber defaults to 4
inspect(FoscOctave("c")); // octaveNumber defaults to 4