* generator/*.cs: implement the interfaces on the adapters too.
Generate an Implementor interface for users which exposes the
methods to implement. Register based on the Implementor sub-iface.
* gtk/*Adapter.custom: custom implementations for the custom
interface members.
* gtk/TreeIter.custom: make UserData public.
* sample/TreeModelDemo.cs: sample for implementing a TreeModel
interface.
svn path=/trunk/gtk-sharp/; revision=86753
* generator/*.cs : refactoring of Parameters class. Added IEnumerable
to Parameters and gracefully handle elem == null instead of special
casing parms == null all over the place. Parameter logic is now Count
driven. [Fixes#71750]
svn path=/trunk/gtk-sharp/; revision=39594
