I've fixed a bug in FGRunways::search(aptid, tgt_hdg) which wasn't working properly for airports with multiple parallel runways. I've also firmed up and pulled out into it's own function the GetReverseRunwayNo code, and done some input checking.
As a result of fixing the above in runways.cxx, I've pulled out the
parallel implementation in the functions that set position by airport and
heading/runway number in fg_init.cxx and called the runways functions
instead.