"General cleanup: Fix several potential segfaults, ensure delete
approach dialog can be exited with the crsr button, implement heading
information in DTO mode, make the comments more useful, and remove old
debugging comments."
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.
