Note entry (chord) playback appreciation

Build 8da37f.

Just a note to say that I love the way that it sounds when you enter a chord now - previously you heard each note as you entered it; now when you add each note to a chord you hear the whole chord. It may just be subjective but I think it slightly speeds up chord entry and it certainly seems to make the input more accurate as you can immediately differentiate between minor and major chords and get a clue if you have entered a note wrong. I found it useful when transcribing an awkward piece where the accidentals on the lower stave get carried on to the upper one due to cross-staff beaming but the aim of the composer setting it out this way was to avoid the accidentals on the top stave and lay out the two hands' work. Hearing all the notes of the chord helps remind one when to change the accidentals or make them invisible.