Don't accidentally set osd_got_home when disarming.
Don't relay on refresh rate in OSD_Func, use actual millis().
In showArrow() only draw the actual arrow, simplify.
Remove a few unneeded globals, make local.
Optional framerate panel for debugging (default off).
If available, use GPS error info to assess precision.
Skip home direction calculation if no GPS updates.
No need to fabs() if the value is square later.
Avoid repeating calculations in home direction calc.
Calculate our own COG if not available from GPS.
Store the absolute home dir in globals, subtract heading locally.