Convert FGRunway to be heap-based, and inherit FGPositioned. This is a large, ugly change, since FGRunway was essentially a plain struct, with no accessors or abstraction. This change adds various helpers and accessors to FGRunway, but doesn't change many places to use them - that will be a follow up series of patches. It's still a large patch, but outside of FGAirport and FGRunway, mostly mechanical search-and-replace.
An interesting part of this change is that reciprocal runways now exist as independent objects, rather than being created on the fly by the search methods. This simplifies some pieces of code that search for and iterate runways. For users who only want one 'end' of a runway, the new 'isReciprocal' predicate allows them to ignore the 'other' end. Current the only user of this is the 'ground-radar' ATC feature. If we had data on which runways are truly 'single-ended', it would now be trivial to use this in the airport loader to *not* create the reciprocal.
Here's part 2 - converting FGFix (the simplest one) to be both heap-based and inherit FGPositioned. One minor benefit from this is replacing some dangerous code in FGFixList which used to return the address of an iterator member ('&it->second'). To keep the diff a sensible size, I'm not updating the callers to use the richer FGPositioned types - i.e replacing separate lat/lon handling with SGGeod. I will make those cleanups, but in future patches.
This is a little intrusive on the KLN89 code, but avoids the wasteful cloning of the airports, runways and navaids which current happens, and also combines the ugly string ordering code.
- Runways are now part of an airport, instead of a separate list
- Runways are no longer represented as a boring struct, but as a class
of their own.
-Improved runway access to unify various runway access methods.
- this exposed a bizarre issue on Mac where dragging in <AGL/agl.h> in
extensions.hxx was pulling in all of Carbon to the global namespace
- very scary. As a result, I now need to explicitly include CoreFoundation
in fg_init.cxx.
- change SG_USING_STD(x) to using std::x
