Includes the rewritten livery scanning code. It might need some more
tweaks to be fast enough, but it at least now doesn't spam the log for
machines that don't have DCS (or Liberation) installed, and it's not
slow until something tries to use it, so until we add the UI we won't
have to pay for it during startup.
pydcs_extensions.__init__ wasn't actually doing anything because without
an __init__.py each of these "packages" was empty. This has been working
by accident because of ai_flight_planner_db.py.
