Small 2D test cas for Maxwell PML seems ok: same results for sf and getdp (order 1 and 2)
NodeSolution for cuts on fine mesh
Keep on going with 3D sphere diffraction case


git-svn-id: https://geuz.org/svn/gmsh/trunk@18584 59c8cabf-10d6-4a28-b43f-3936b85956c4