and in an attack of madness, changes almost all file plug-in
code to use GFile instead of filenames, which means passing
the GFile down to the bottom and get its filename at the very
end where it's actually needed.
It's an ancient concept from ancient times when we didn't have URIs
and only filenames (not to speak of GFile), and actually even from
before the ancient time before that ancient time when we first had
ones and zeros, and only had zeros.
