Region#show return currentView

Adds the capability to write

    myRegion1.show(new MyLayout1());
    myRegion1.currentView.myRegion2.show(new MyLayout2());
    myRegion1.currentView.myRegion2.currentView.myRegion3.show(new MyLayout3());
    ... etc

as 

    myRegion1.show(new MyLayout1()).myRegion2
             .show(new MyLayout2()).myRegion3
             .show(new MyLayout3()) ... etc