* gda/Makefile.am : add new custom.
* gda/XmlConnection.custom : add backcompat static ctor.
* generator/ClassBase.cs : refactor lookup logic to here from Ctor
and improve the collision resolution.
* generator/Ctor.cs : refactor to use MethodBase.
* generator/Makefile.am : add new file.
* generator/MethodBase.cs : new base class for ctors and methods.
* generator/Method.cs : refactor to use MethodBase.
* generator/StructBase.cs : move some logic from here to Ctor.
* gnome/CanvasPathDef.custom : add backcompat static ctor.
* gnome/GPPath.custom : add backcompat static ctor.
* gnome/Makefile.am : add new custom.
* gtk/Gtk.metadata : mark a colliding Button ctor shared.
svn path=/trunk/gtk-sharp/; revision=39431
