gobject: Deprecate GParameter
gobject: Deprecate GParameter

GParameter is a rarely used type and not introspectible.

https://bugzilla.gnome.org/show_bug.cgi?id=709865

johne53/MB3Glib,endlessm/glib,endlessm/glib,endlessm/glib,johne53/MB3Glib,johne53/MB3Glib,endlessm/glib,johne53/MB3Glib,endlessm/glib,johne53/MB3Glib,johne53/MB3Glib