Changed "USB" to "DebugPort"
Tidy up of blue wire data frames and passing about by reference instead of just the data buffer.
Added AppInventor application
Changed Tx headers to [OEM] and [BTC] for the OEM controller and this Bluetooth controller.
Added #ifdefs to accomodate Mega and ESP32.
Built and tested on ESP32, Serial1 talks to heater OK using standard pin numbering :-)
If found, it parrots the settings, but allows on/off commands to be inserted by a user.
If no other controller detected, it falls back and delivers our settings each second.
Currently reports all packets to USB, but will move onto Bluetooth delivery of heater data soon.
