BFCOMPAT - improve wind and airspeed fields and labels

[rmaia3d]

• Add labels, A for airspeed and W for horizontal wind speed.
• Fix the horizontal wind direction arrows, to use the default (and existing) BF direction arrows instead of the customized ones.

This makes the wind speed and direction calculation usable in the O3 OSD modes.

[kibbycabbit]

That really makes sense. I love that idea.

Although may I suggest add a little more clarification.. We do have Airspeed, ground (GPS) speed, wind speed..

Unsure if it should be left or right ident alignment:

A ## km/h
G ## km/h
W ## km/h (direction arrow)