Play sound for each note in Tuner

Add a virtual keyboard or diapasone for intonation practce

We could add such a feature to the tuning part of the app

Merged "Note" #630

Merged "Pitch note" #642

"When tuning, having a way of hearing the note that you are trying to tune to would be really helpful. if I was trying to tune an E string this feature would mean that I could tap the E on the screen and it would play an E. So I can tune by using my ear."

Merged "Tuner: generate tone like pitch pipe" #542