Feature/pedal banking

This PR adds the ability to bank chords by depressing the sustain pedal. When the sustain pedal is depressed, either by clicking the pedal on the UI or using an actual MIDI pedal connected to the keyboard (i.e. Yamaha FC5), the notes that are playing are immediately banked. 

This was requested by Rowland on 3/31/14.

@jazahn Review?