Check for window best size in wxPersistentTLW

Ensure that the restored size is at least equal to the best size of the
window to avoid cutting off parts of it in (a common) case when a newer
version of the program adds new UI elements, thus increasing the window
best size and possibly making the previously stored size too small.

include/wx/persist/toplevel.h

@@ -116,7 +116,14 @@ public:
         }
 
         if ( hasSize )
+        {
+            // a previous version of the program could have saved the window
+            // size which used to be big enough, but which is not big enough
+            // any more for the new version, so check that the size we restore
+            // doesn't cut off parts of the window
+            size.IncTo(tlw->GetBestSize());
             tlw->SetSize(size);
+        }
 
         // note that the window can be both maximized and iconized
         bool maximized;