CHANGE: Dropped need for QextSerialPort, now using Qt's native QSerialPort library.
CHANGE: Arduino MEGA variants use the SECOND serial port for communication leaving the USB port free for debugging.
FIX: uchar_prog definition obsoleted, changed to PROGMEM.
FIX: Fixed conditional compilation so that it is done for all APPLE-based OSes instead of just OSX.
FIX: Compilation now working again under Windows, Linux AND with multicore build.