Most subsystems are now created via the subsystem manager using the global
subsystem registrations.
The FGGlobals add_subsystem() and add_new_subsystem() methods have been removed
as the subsystem manager addition and creation function interface now exceeds
the functionality of these helper functions.
As this code has significant bit-rot and requires a lot of work to compile and
run again, it is currently deactivated.
The test also writes to the files "/Users/jmt/Desktop/airways.kml" and
"/Users/jmt/Desktop/procedures.kml" and would need to be modified to write to a
temporary directory and the file contents reread and checked by the test.