De/Serialization for wavefront object files

Adds to export/import topology as wavefront object files. This enables users to view/edit/use topology inside 3rd party 3D editors

ff/WavefrontSerializer.cpp

@@ -2,7 +2,7 @@
 //
 //  BornAgain: simulate and fit reflection and scattering
 //
-//! @file      ff/WavefronSerializer.cpp
+//! @file      ff/WavefrontSerializer.cpp
 //! @brief     Implements serialization and deserialization for polyhedra.
 //!
 //! @homepage  https://jugit.fz-juelich.de/mlz/libformfactor