[Feature Idea] Add the ability to see "good chords" for a scale.

[Sintrastes]

It would be really useful if for every scale, we had a way of calculating "good chords" for that scale.

i.e. "What chords can I reasonably solo over this scale with?"

Potentially we could even give the option of displaying a list of these chords with a scale diagram, which might be useful as a "cheat sheet" for soloing.