Clean up visuals of elements test

Elements were not being displayed correctly on small screens,
i.e. devices. Should anchor these to the bottom, rather than center.
Also fix layout element child positions, as opacity is not used to
determine placement - use visible property instead.

Change-Id: I9fff7e64f3f03f1a4d60a242fb8f95629da6f7c9
Reviewed-by: Michael Brasser <michael.brasser@nokia.com>