0.01: attempt to import
0.02: better GPS support, adding altitude and temperature support
0.03: minor code improvements
0.04: make height auto-calibration useful and slow ticks to save power
0.05: add ability to navigate to waypoints, better documentation
0.10: lots of updates
	acknowledge commands by	vibration and message
	ui tweaks -- bigger font, compressing uninteresting info
	display	meters up/down
	display	pressure trend
	adjust GPS on/off algorithm for more reliable fix
	display	warnings when GPS altitude does	not match baro
0.11: implement sunrise/sunset times
