The `outdir` and `docbook` parameters are passed to the
`DocbookCodeGenerator` constructor, but these parameters are only
used at docbook generation, which is optional.
The parameters have been removed from the class creation and added
to the `generate` method, where they are actually being used.
https://bugzilla.gnome.org/show_bug.cgi?id=791015
In addition to code, gdbus-codegen can also generate docbook
documentation for DBus interfaces. There's no good reason why
the newly added --output-directory option shouldn't apply to
those generated files as well.
https://bugzilla.gnome.org/show_bug.cgi?id=783201
Most changes were just replacing usage of "has_key" with "in".
Also updated the sorting function which was simplified and
changed to a "key" function instead of "cmp" (which is no longer
supported in python3. Verified everything builds with
python 2.7 and 3.
https://bugzilla.gnome.org/show_bug.cgi?id=678066
