0027398: Integrate Qt Browser Widget to Open CASCADE Technology

The following implementation has been made:
- CMake procedure is extended to compile Qt tools. This is optional and is handled by USE_QT_TOOLS option(OFF by default)
- It is possible to build Qt tools using Qt5 or Qt4, it is settled with USE_QT4 option.
- Sample of DFBrowser tool is available in samples/tools/TInspectorEXE. It is build with tools, executable is placed in binaries. To start the sample, use dfbrowser.bat command.
- DFBrowser tool may be started from DRAW

tools/DFBrowser/DFBrowser_TreeView.cxx

@@ -0,0 +1,37 @@
+// Created on: 2017-06-16
+// Created by: Natalia ERMOLAEVA
+// Copyright (c) 2017 OPEN CASCADE SAS
+//
+// This file is part of Open CASCADE Technology software library.
+//
+// This library is free software; you can redistribute it and/or modify it under
+// the terms of the GNU Lesser General Public License version 2.1 as published
+// by the Free Software Foundation, with special exception defined in the file
+// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
+// distribution for complete text of the license and disclaimer of any warranty.
+//
+// Alternatively, this file may be used under the terms of Open CASCADE
+// commercial license or contractual agreement. 
+
+#include <DFBrowser_TreeView.hxx>
+
+// =======================================================================
+// function : SetPredefinedSize
+// purpose :
+// =======================================================================
+void DFBrowser_TreeView::SetPredefinedSize (int theDefaultWidth, int theDefaultHeight)
+{
+  myDefaultWidth = theDefaultWidth;
+  myDefaultHeight = theDefaultHeight;
+}
+
+// =======================================================================
+// function : sizeHint
+// purpose :
+// =======================================================================
+QSize DFBrowser_TreeView::sizeHint() const
+{
+  if (myDefaultWidth > 0 && myDefaultHeight > 0)
+    return QSize (myDefaultWidth, myDefaultHeight);
+  return QTreeView::sizeHint();
+}