Any annotation where the key has a dot in the name will go into the
attribute list. For example
* @arg: (foo.bar baz): some arg
the parameter @arg will get the attribute with key foo.bar and value
baz. This also works for.
* Returns: (foo.bar2 baz2): the return value
Also add tests for this new feature.
See https://bugzilla.gnome.org/show_bug.cgi?id=571548
Signed-off-by: David Zeuthen <davidz@redhat.com>