I made a number of fixes for the interface module;
1. Removed unnecessary includes (especially for the ACIS output, which doesn't require any special headers that prevents it from beeing compiled).
2. Removed conditional compiling (which seems to be there for no good reason, what is the variable OLIVER supposed to mean? Why should TET-write be conditional?).
3. Added support for writing VTU-files (from VTK)
4. Doxygen documentation for all functions in writeuser.hpp
5. Renaming wuchemnitz, read_fnf_mesh, readtetmesh, to have a more consistent naming.
6. Renamed writeuser.hpp to interface.hpp (it doesnt just do writing, and it's not specific to writeuser.cpp, i believe the name is much more appropriate)
7. Removed unnecessary use of keyboard extern in header.
8. Fixed DOLFIN output (also added 2D mesh and more element types)
9. Added missing functions to the list so netgen can use them
10. Split up VRML and STL and FEPP to seperate files.
11. Removed redundant CSGGeometry parameter in all functions which doesn't actaully use it.
12. Removed \r line endings in gmsh2 output (they show up when editing in VI, i had to change to be able to read the code which i used as a reference to write the VTU exporter).
13. Added namespace in header.
These changes will require two modifications to the files in ng/, namely moving the header outside the external namespace and changing the name to interface.hpp instead.
About the external namespaces. I dont understand why this was done? To be honest, i get the feeling it was just beeing lazy as most of the sources was maybe not part of the netgen namespace to begin with.