Add the possibility to disable invisible wxDataViewCtrl items.

Add new wxDataViewModel::IsEnabled() and wxDataViewListStore::IsEnabledByRow()
methods and implement support for actually disabling the items in wxOSX/Cocoa
native implementation of wxDataViewCtrl and limited support for it in the
generic version.

We need to implement this in wxGTK using GtkCellRenderer "sensitive" propriety
later.

Closes #12686.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66403 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/dataview/dataview.cpp

@@ -653,6 +653,10 @@ void MyFrame::BuildDataViewCtrl(wxPanel* parent, unsigned int nPanel, unsigned l
                                         wxDefaultSize, style );
             m_ctrl[2] = lc;
 
+            MyListStoreDerivedModel* page2_model = new MyListStoreDerivedModel();
+            lc->AssociateModel(page2_model);
+            page2_model->DecRef();
+
             lc->AppendToggleColumn( "Toggle" );
             lc->AppendTextColumn( "Text" );
             lc->AppendProgressColumn( "Progress" );