Adds a 2d test on a sphere tet grid (
sphere.msh). I also committed a
sphere_quad.msh grid which has some nasty distorted quad elements.
Unfortunately I currently get for both grids:
Dune::InvalidStateException [decompose:/Users/pumbaa/dune-master/dumux/dumux/discretization/cellcentered/wmpfa/facedatahandle.hh:101]: CoNormal decomposition not found
although the tet version of the grid looks fairly nice.
I wanted to use this test to check if it works in 3D.
For now it's only Dirichlet but it should be relatively easy to try Neumann boundaries.