Add body:ecefx, body:ecefy and body:ecefz or body:facing suffixes

[Earth-And-Moon]

body:ecefx, body:ecefy and body:ecefz would be unit vectors that would point from a body's center to the directions of a body's local ECEF x (0° lat and long), y (0° lat, 90° long) and z (90° lat, any long) axes (in ship coordinate frame). Basically a body equivalent to ship:facing. This can also be implemented as body:facing just like on vessel:facing.

This would be useful for writing guidance systems.

(from [Wikipedia](https://en.wikipedia.org/wiki/Earth-centered,_Earth-fixed_coordinate_system))

[nuggreat]

kOS already supplies everything you need to create that.