Chord memory function with basspedal and midi-shield

Using Arduino Audio
12

The chords are defined in Chords.hpp. Just add some more.

For example:

const Chord<4> MajorAndBass = {{M3, P5, -P8, -2*P8}};

This is a major chord (major third, perfect fifth), and two bass notes (one octave lower, and two octaves lower).