Rather than requiring all the arguments to be placed as member variables to
the functor you can now pass extra arguments that will be added to the functor
call signature.

So for example:

  vtkm::ForEach(functor, vtkm::TypeListTagCommon(), double{42.0}, int{42});

will be converted into:

  functor(vtkm::Int32, double, int)
  functor(vtkm::Int64, double, int)
  functor(vtkm::Float32, double, int)
  functor(vtkm::Float64, double, int)
  ...