Fix key signature setting to accept an enharmonic pitch

Fix key signature setting to accept an enharmonic pitch

If the user asks for a key with a specific, real, name such a Cb or B,
then the user will get that key.

But if the user asks for a key that is not a real name, (such as B#),
then the user will get a real key that is enharmonic, (such as C in
this case).