QmlDesigner.PropertyEditor: removing old legacy files

I kept them as reference, but they are not needed anymore.
The QtQuick 2.0 port is done.

Change-Id: Ieb75d506a45636a17adc3c78d7beca6d5c1fd211
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Marco Bubke <marco.bubke@digia.com>