It looks like the deserialisation function in GSocketControlMessage can
potentially leak a reference to the class structure of a
GSocketControlMessage subclass (although the particular code path is
probably never hit).
Clean up the code a bit.
Also, make sure that the GUnixCredentialsMessage type is registered
before attempting deserialisation.
Closes bug #629687.
This adds:
GInitable - failable object constructor interface
GAsyncInitable - async failable object constructor interface
GSocket - Platform independent lowlevel berkely socket style object
GSocketControlMessage - For passing control messages over GSocket
GUnixFDMessage - unix fd passing socket control message
Some changes were done during the import from gnio to make things
work in glib. For instance, types were moved to other headers, header
file boiler plate were updated to glib style and gio.symbols stuff
was added.
