Add GPIO and MIDI Buttons for Bank selection

[diyelectromusic]

We should add equivalents of:

ButtonPinPgmUp=0
ButtonActionPgmUp=click
ButtonPinPgmDown=0
ButtonActionPgmDown=click

and

MIDIButtonPgmUp=0
MIDIButtonPgmDown=0
MIDIButtonTGUp=0
MIDIButtonTGDown=0

for banks which will act on either Voice banks or Performance banks just like the above depending on the setting of PerformanceSelectChannel.

Kevin