Add missing DeleteAllColumns

interface/wx/listctrl.h

@@ -368,6 +368,13 @@ public:
                 const wxValidator& validator = wxDefaultValidator,
                 const wxString& name = wxListCtrlNameStr);
 
+    /**
+       Delete all columns in the list control.
+
+       @return @true if all columns were successfully deleted, @false otherwise.
+    */
+    bool DeleteAllColumns();
+    
     /**
         Deletes all items in the list control.