Add extern template decls for vtkPythonArgs::Array
This is needed to avoid "no definition is available" clang warnings for C++11 compilation.
I've also added VTK_USE_EXTERN_TEMPLATE to vtkPythonConfigure.h to avoid code duplication.
This is needed to avoid "no definition is available" clang warnings for C++11 compilation.
I've also added VTK_USE_EXTERN_TEMPLATE to vtkPythonConfigure.h to avoid code duplication.