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_AttributePaneCreatorAPI.hxx

@@ -0,0 +1,42 @@
+// 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_AttributePaneCreatorAPI_H
+#define DFBrowserPane_AttributePaneCreatorAPI_H
+
+#include <Standard.hxx>
+#include <Standard_Macro.hxx>
+
+class DFBrowserPane_AttributePaneAPI;
+
+//! \class DFBrowserPane_AttributePaneCreatorAPI
+//! \brief An interface to create attribute panes by attribute name.
+class DFBrowserPane_AttributePaneCreatorAPI
+{
+public:
+
+  //! Constructor
+  DFBrowserPane_AttributePaneCreatorAPI() {}
+
+  //! Destructor
+  virtual ~DFBrowserPane_AttributePaneCreatorAPI() {}
+
+  //! Creates attribute pane for attribute types
+  //! \param theAttributeName a standard type of attribute
+  //! \return an attribute pane if it can be created for this type
+  virtual DFBrowserPane_AttributePaneAPI* CreateAttributePane (const Standard_CString& theAttributeName) = 0;
+};
+
+#endif