message: Remove warning in Visual Studio
  The following warning is removed:
  Visual Studio 14.0
  1. warning C4275: non dll-interface class 'std::exception' used as
  base for dll-interface class 'vtkpugixml::xpath_exception'
diff: @@ -1251,6 +1251,12 @@ namespace pugi
  };
  #ifndef PUGIXML_NO_EXCEPTIONS
  + #if defined(_MSC_VER)
  + // C4275 can be ignored in Visual C++ if you are deriving
  + // from a type in the Standard C++ Library
  + #pragma warning(push)
  + #pragma warning(disable: 4275)
  + #endif
  // XPath exception class
  class PUGIXML_CLASS xpath_exception: public std::exception
  {
  @@ -1267,6 +1273,9 @@ namespace pugi
  // Get parse result
  const xpath_parse_result& result() const;
  };
  + #if defined(_MSC_VER)
  + #pragma warning(pop)
  + #endif
  #endif
  // XPath node class (either xml_node or xml_attribute)
  