Nested views throws TopologicalSort exception if they reference Pos/Dim to the root view.

[BDisp]

Describe the bug
Referencing a root Pos/Dim from a recursive nested views will throws a TopologicalSort exception.

To Reproduce
Steps to reproduce the behavior:
Running this code will throw the error.

	Application.Init ();

	var top = Application.Top;
	var win = new Window ();
	var view1 = new View ("View1") {
		Id = "view1",
		X = Pos.Left (win) + 1,
		Y = Pos.Top (win) + 1,
		Width = Dim.Width (win) - 2,
		Height = Dim.Height (win) - 2
	};
	var view2 = new View ("View2") {
		Id = "view2",
		X = Pos.Left (win) + 2,
		Y = Pos.Top (win) + 2,
		Width = Dim.Width (win) - 4,
		Height = Dim.Height (win) - 4
	};
	view1.Add (view2);
	win.Add (view1);
	top.Add (win);

	Application.Run (top);
	Application.Shutdown ();

Expected behavior
Running without throw any exception when the root in the tree isn't null from the nested view.

[BDisp]

Closing this because the fix was included in the v2 on PR #2385.