* generator/ClassBase.cs : remove default ctor generation and
hasDefaultConstructor field.
* generator/Ctor.cs : chain to base (IntPtr.Zero).
* generator/StructBase.cs : remove hasDefaultConstructor usage.
* glib/Object.cs : remove Object () ctor. Add Ben's GetGType
method, although nothing uses it yet. Still working on integrating
the remainder of Ben's patch.
* gtk/Gtk.metadata : remove all the disabledefaultctor rules.
* */*.custom : add base (IntPtr.Zero) or this (...) chaining for
all ctors.
svn path=/trunk/gtk-sharp/; revision=25184