Generate introspection.[ch] from the XML files; add missing methods to them
This is the first part of #73:
- The introspection data is generated automatically from the DBus XML files. If you change those files, the introspection data will be regenerated.
- The XML files have all the properties/methods/signals that they were missing from the hand-modified introspection data.
The next part is #75, to audit the C marshalers to make sure they match the XML.