Action listeners changes

Issue #83
In Wpf: if element was searched not from window but from previously found Custom Control then action listener can be null (because Custom Control in wpf have no mapping attribute to initialize it's type). But Action Listener property however is not null. Made refactoring to remove action listener private variable as it not that usefull as should and also make a better use of methods ActionPerform() and ActionPerform(UIItem) in UIItem. Tests added. Old tests also pass.