0022877: Implementation of DRAW commands for non-regression testing:

- TKIVtkDraw toolkit provides IVtk packages functionality in DRAW.

- it allows to create VTK interactive view in regular or virtual mode (virtual windows),
  display OCC objects and dump them.

- TKIVtkDraw provides also test commands: ivtlinit, ivtkdisplay, ivtkerase, ivtksetdispmode,
   ivtksetselmode, ivtkmoveto, ivtkselect, ivtkfit, ivtkdump, ivtkbgcolor.

Corrected offscreen rendering mode.

Moved vinit command from /v3d/begin script to avoid unused occ view in ivtk tests.

src/IVtkDraw/IVtkDraw.hxx

@@ -0,0 +1,45 @@
+// Created on: 2012-02-03 
+// 
+// Copyright (c) 2012-2014 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 _IVtkDraw_HeaderFile
+#define _IVtkDraw_HeaderFile
+
+#include <MMgt_TShared.hxx>
+#include <Standard.hxx>
+#include <Standard_Macro.hxx>
+
+class Draw_Interpretor;
+class MMgt_TShared;
+
+class IVtkDraw
+{
+public:
+
+  DEFINE_STANDARD_ALLOC
+
+  Standard_EXPORT   static  void ViewerInit (Standard_Integer thePxLeft,
+                                             Standard_Integer thePxTop,
+                                             Standard_Integer thePxWidth,
+                                             Standard_Integer thePxHeight);
+
+  Standard_EXPORT   static  void Factory (Draw_Interpretor& theDI);
+  Standard_EXPORT   static  void Commands (Draw_Interpretor& theCommands);
+
+private:
+  Standard_EXPORT   static const Handle_MMgt_TShared& WClass();
+};
+
+#endif
+