Simplify ArrayHandleImplicit and ArrayHandleTransform templates

Both vtkm::cont::ArrayHandleImplicit and vtkm::cont::ArrayHandleTransform take the value type as a template parameter T. This is unnecessary in c++11 as the value type can be inferred from the FunctorType using decltype.

Value type for ArrayHandleImplicit:

using ValueType = decltype(FunctorType{}(vtkm::Id{}));

Value type for ArrayHandleTransform:

using ValueType = decltype(FunctorType{}(typename HandleType::ValueType{}));