QmlDesigner.SubComponentManager: Do not parse if detached

If detached from rewriter do not parse directories.

Change-Id: Ie07e732d5e09b337d43221df4aa88c7e62aac55b
Reviewed-by: Marco Bubke <marco.bubke@digia.com>
QmlDesigner.ItemLibrary: adding SplitView

Change-Id: I3bab4c2749ef87058015ead3218c5dc6c14bee98
Reviewed-by: Marco Bubke <marco.bubke@digia.com>