QmlDesigner.PropertyEditor: Adding missing control for TransformOrigin

Now the TransformOrigin can be edited again.

Change-Id: Ie89c7aed2f092f303286091cc44655ff70dae777
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner.ItemLibrary: Allow bindings without extra source file

This makes drag and drop faster than merging code.

Task-number: QTCREATORBUG-9361
Change-Id: If9779d7439ea41edfb80c08161b7ef3d0f08cf41
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>