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.hxx

@@ -0,0 +1,54 @@
+// 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 DFBrowser_TreeView_H
+#define DFBrowser_TreeView_H
+
+#include <Standard.hxx>
+#include <Standard_Macro.hxx>
+
+#ifdef _MSC_VER
+#pragma warning(disable : 4127) // conditional expression is constant
+#endif
+#include <QTreeView>
+
+//! \class DFBrowser_TreeView
+//! Extended tree view control with possibility to set predefined size.
+class DFBrowser_TreeView : public QTreeView
+{
+public:
+
+  //! Constructor
+  Standard_EXPORT DFBrowser_TreeView (QWidget* theParent)
+  : QTreeView (theParent), myDefaultWidth (-1), myDefaultHeight (-1) {}
+
+  //! Destructor
+  virtual ~DFBrowser_TreeView() {}
+
+  //! Sets default size of control, that is used by the first control show
+  //! \param theDefaultWidth the width value
+  //! \param theDefaultHeight the height value
+  Standard_EXPORT void SetPredefinedSize(int theDefaultWidth, int theDefaultHeight);
+
+  //! Returns predefined size if both values are positive, otherwise parent size hint
+  Standard_EXPORT virtual QSize sizeHint() const Standard_OVERRIDE;
+
+private:
+
+  int myDefaultWidth; //!< default width, -1 if it should not be used
+  int myDefaultHeight; //!< default height, -1 if it should not be used
+};
+
+#endif