Short Description: Qt4-implemented Accounting View: "Layout Network" Operation
Bug Number: n/a
Release notes (y/n): no
For Release Nums: 6.1

Implemented the "Layout Network" operation in the new Qt4-implemented 
Accounting View.

Also: Disabled this operation in the old Qt3-implemented Accounting View.
It was sometimes crashing there, and since that view is going away soon,
it seemed best to just disable it.

---------------------
WorkspaceGfxScene.hpp
WorkspaceGfxScene.cpp
---------------------

method WorkspaceGfxScene::layoutNetwork() implemented for the new Qt4 
"Graphics View" implemented Accountint View, based on original Qt3 
"Canvas View" implementation in Q3GUI/AccountingCanvas.cpp.

One difference with respect to the old and new coordinate system 
implementations is that, since the algorithm is dealing will only 
application-domain coordinates in the Simulation and Accounting Geometries, 
no vertical reversal of coordinates is needed in the layout computation, 
(in the Qt4-implemented views).

New data member:
  bool _layoutNetwork_inProgress;

------------------
RwGraphicsView.hpp
RwGraphicsView.cpp
------------------

Added utility to "send" a new message to the Workspace status bar.
  void sendStatusBarMessage (const QString&);

The first use of this is to display this message in the Workspace status
bar during the Layout Network operation:

  "Laying out accounting network"

--------------------------
Q3GUI/AccountingCanvas.cpp
--------------------------

The Layout Network operation in the OLD Qt3 Accounting View is sometimes
crashing.  Since this old view will soon be dropped, in favor the new Qt4
implemented Accounting View, the Layout Network operation here is being
disabled.  A popup is shown with this message:

  "The Layout Network operation is no longer implemented in this view."

---