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/DFBrowserPane/DFBrowserPane_TDataStdTreeNodeModel.hxx

@@ -0,0 +1,58 @@
+// 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. 
+
+#ifndef DFBrowserPane_TDataStdTreeNodeMode_H
+#define DFBrowserPane_TDataStdTreeNodeMode_H
+
+#include <Standard.hxx>
+#include <TDF_Attribute.hxx>
+#include <TreeModel_ModelBase.hxx>
+
+#include <QObject>
+#include <QHash>
+#include <QByteArray>
+
+//! \class DFBrowserPane_TDataStdTreeNodeModel
+//! \brief It builds a tree of items for the given tree node attribute.
+class DFBrowserPane_TDataStdTreeNodeModel : public TreeModel_ModelBase
+{
+  Q_OBJECT
+public:
+
+  //! Constructor
+  Standard_EXPORT DFBrowserPane_TDataStdTreeNodeModel (QObject* theParent);
+
+  //! Destructor
+  virtual ~DFBrowserPane_TDataStdTreeNodeModel() Standard_OVERRIDE {};
+
+  //! Initializes the tree model by the attribute
+  //! \param theAttribute a current attribute
+  Standard_EXPORT void SetAttribute (const Handle(TDF_Attribute)& theAttribute);
+
+  //! Returns model index by the attribute.
+  QModelIndex FindIndex (const Handle(TDF_Attribute)& theAttribute) { (void)theAttribute; return QModelIndex(); }
+
+  //! Returns count of columns in the model.
+  //! \param theParent an index of the parent item
+  //! \return integer value
+  virtual int columnCount (const QModelIndex& theParent = QModelIndex()) const Standard_OVERRIDE
+  { (void)theParent; return 1; }
+
+private:
+
+  Handle(TDF_Attribute) myAttribute; //! the parent attribute
+};
+
+#endif