[Vala] GIO: nullable parameters, File object construction

[Frederik <scumm_fredo gmx net>]

I think in the GIO vapi bindings there are more parameters that should
be marked as nullable. For example: "etag" as in File.replace() or
"progress_callback" as in File.move().

btw, is it an inconsistency that File objects get constructed by

        File.new_for_commandline_arg()
        File.new_for_path()
        File.new_for_uri()

instead of

        new File.for_commandline_arg()
        new File.for_path()
        new File.for_uri()

?

Regards,

Frederik