- build and write edge and corner connectivity for FEM solvers
  - removed unused supernode
  - added local edge pointer

…y, needed for FEM solver

…rks, but compiles and runs.

…d periodic edge...)

…nd FEM edges, write EdgeInfo and EdgeConnectInfo to HDF5 file (to be filled)

…lled edgeInfo and edgeConnectionInfo. compiles and runs, but result not yet checked.

…output to hdf5 still missing.

… and fully periodic boundaries. This also includes edge and vertex information.

…ged a little, but still there are bugs with periodic edges and vertices...

…ult is false, such that previously running tests work. added a new tutorials folder with cases that test that new feature explicitly, and the periodic ones still fail...

…s all examples, for all kinds of periodic meshes (all internal checks go through). Output file data still need to be checked if they are correct.

- its important to check for the periodic edges, when both firstlocaledges  already exist, if they point onto the same, and if not re-pointer.
  this then makes all common periodic edges pointing to the same firstlocalEdge. all other edges are already unique, and thus always point to one firstlocaledge.
- Analogously done for the periodic vertices.
output to hdf5:
- add a FEMconnect="OFF"/"ON" variable, to be able to know if the edge and vertex connectivity has been generated and written to file (paramterflag `generateFEMconnectivity=T`)
- changed from modified ElemInfo back to original ElemInfo, moved edge and vertex offsets into a new FEMElemInfo.
- added vertex connectivity information to hdf5.
- updated the documentation of the meshformat.

…s and vertices. In mesh_tools: added vtk output of Debugmesh_Faces for UniqueFaceIDs and Debugmesh_Edges for FEMedgeIDs and FEMvertexIDs.

…ultiple periodic cases.

…hich fixes case tutorials/4-05. the problem was that the triangles were not created, and the fill2.5mesh did not see this. Added abort in Fill2.5 mesh, if anything else than prism or hexa are in the mesh. In the screen output for the element types, the names prism and pyramids had to be interchanged.

…e same problem.

…opr can check it. A FEM solver should run on these meshes, to be sure.

…CornerConnectivity