Update shape handling

Update shape handling

For toplevels, never apply clip as shape, instead apply shape.
This way we don't have to re-set it all the time as the window size
changes. Furthermore, this change fixes unsetting a shape on a
toplevel window which didn't actually unset the shape before.

Additionally we never apply clips as shape if the shape would just
be the same as the regular window size. This means we won't unnecessarily
add a useless shape to most native child windows (and additionally this
helps apps that do weird X stuff that don't expect these shaped windows).