Deal with Vector_d as well

Kernel_d/include/CGAL/Kernel_d/Vector_d.h

@@ -71,7 +71,13 @@ class Vector_d : public pR::Vector_d_base
 
   Vector_d(const Self& v) : Base(v) {}
   Vector_d(const Base& v) : Base(v) {}
+  
+#ifndef CGAL_CFG_NO_CPP0X_DELETED_AND_DEFAULT_FUNCTIONS
+  Self&
+  operator=(const Self& v)=default;
+#endif  
 
+  
   Direction_d<R> direction() const { return Base::direction(); }
 
   FT operator* (const Self& w) const