Fix script failure under windows

Rely on argpaser for checking that all arguments are present.
Removed redundant argument check in main().

Added '--debug' option and print_dbg method.

Rethink failures on overrides. Remove well know path fallbacks,
error exit when override file is missing.

In well-known path search for preferences.txt, do not assume true.
Make failure to find an error exit event.

When Windows has two preferences.txt files and they have different
values for caching and globals.h is used, error exit. It is not
possible to know from the script which is being used.