manifold projection (i.e. sphere) does not project

I Added the default projection block to the simplex-testgrid-2-3.dgf that is used with test-alugrid and it turns out, that on refinement the sphere is not projected.

This makes sense in principle, as there are no boundary faces to project, because we have a manifold. So the question is, do we want a different way of handling manifolds?

Basically to be complete, we would need a boundary projection and a manifold projection. The manifold projection would have to be applied to the fake 2d boundary, and the boundary projection would have to be applied to the actual boundary (in the case of a sphere there is none)

I think we had a discussion, when I implemented this, but I am not sure, what the outcome was.