KitInformation: Delete subwidgets in destructor

Change-Id: I7e0a6d457aa26748758b6402955c81eae2c94782
Reviewed-by: hjk <hjk121@nokiamail.com>
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
QmlDesigner.PropertyEditor: initial prototype for QtQuick 2

Change-Id: I85eac02934cd5f7f2f4664b9642c55bb3a23aa1e
Reviewed-by: Marco Bubke <marco.bubke@digia.com>