Retrieves a padtemplate from element_class with the given name.
> If you use this function in the GInstanceInitFunc of an object class
> that has subclasses, make sure to pass the g_class parameter of the
> GInstanceInitFunc here.
the name of the gstreamer.PadTemplate to get.
the gstreamer.PadTemplate with the
given name, or NULL if none was found. No unreferencing is