0029792: Add ::IsParallel method to GeomAPI_Extrema* classes

Add IsParallel() methods for classes:
- GeomAPI_ExtremaCurveCurve
- GeomAPI_ExtremaCurveSurface
- GeomAPI_ExtremaSurfaceSurface

src/GeomAPI/GeomAPI_ExtremaSurfaceSurface.hxx

@@ -128,6 +128,12 @@ Standard_EXPORT operator Standard_Integer() const;
   //! 1,NbExtrema ], where NbExtrema is the
   //! number of extrema computed by this algorithm.
   Standard_EXPORT Standard_Real Distance (const Standard_Integer Index) const;
+
+  //! Returns True if the surfaces are parallel
+  Standard_Boolean IsParallel() const
+  {
+    return myExtSS.IsParallel();
+  }
   
   //! Returns the points P1 on the first surface and P2 on
   //! the second surface, which are the ends of the