How To Adjust Teensyduino’s MIDI Channel Numbering

Teensyduino (Teensy + Arduino) counts MIDI channel numbers from 1 - 16. However, when using bitwise operations, I find it useful to deal with MIDI channel numbers as a nibble from 0 - 15.

This numbering can be changed, as follows. This will only change it when receiving MIDI in Teensyduino via handler functions.