Add symbols to gps coord widget
Add option and disable buttons code for now
Add imperial units to a few widgets. Re-arrange tab 1 for flight testing
Rename relative altitude widget to home altitude widget
Update gps status widget
Modify radar widget: remove plane and use home direction widget on the center, also add a frame around the widget
Reduce rx fifo size and remove overflow debug msg from isr
Add home detection, flight start and flight end