Add geo-fence UAVOs.
Updated coordinate_conversions to use defines from physical_constants.h.
Added DotProduct() to coordinate_conversions.c. DotProduct() computes the
dot-product, that is to say "inner product", of two 3D vectors.
Added geofencing module for flight controller. The module tests for
intersections between a ray and a triangular mesh comprising the walls of
the geofence. The module sets three alarm states:

1) all is normal
2) the vehicle is close to the boundary
3) the vehicle has crossed the boundary.
Added Geo-fence as an additional model controller. In case the model flies
out of the boundary, it goes into a soft-crash mode. If things are fatally
wrong geo-fence puts the model into a hard crash.
Add target support for geofencing.

Changed explicit enum types for unit8_t because posix compilation was
failing.