Ensure all FGPositioned related functions return SGSharedPtr
instead of raw pointers to allow automatic conversion to
nasal ghosts without custom helper functions.
For now it is available in the positioned Nasal
module. FGAirport is fully ported, but especially
procedures/navaids and free functions are still
missing.
This was a bogus concept, either runways have a reciprocal or not (if singled-ended), really this was simply exposing an artefact of the apt.dat encoding. Change to an API which gives what is actually wanted - the ability to extract an airport's runways without any reciprocals included.
