Fix for TextCtrl problem as reported by Vegh

Move definition of wxMenuItem to /gtk/menuitem.h
  Radical change of how to insert a child into a
    paren window. As C++ doesn't have any VMT in
    a class's consructor, I have to use a callback.
  Fixed culumn resizing bug in wxListCtrl
  Fixed menu height bug in MDI code


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@955 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk1/treectrl.cpp

@@ -132,6 +132,10 @@ printf("5\n");
   SetName(name);
   SetValidator(validator);
 
+printf("Robert's new insertion code :-)\n");
+  m_parent->AddChild( this );
+  (m_parent->m_insertCallback)( m_parent, this );
+  
 printf("postcreate\n");
   PostCreation();