Fixes multiple copyright messages in the doxygen docu.

ag '\\file' -L --ignore=ThirdParty *Lib |xargs  sed -i 's/\(.*\)\\copyright/\1\\file\n\1\\copyright/'

std::vector<std::size_t> _ids_of_active_elements.

due to its std::unique_ptr type instance.

Find a boundary mesh in the list of meshes instead of using GeoObjects
and pass it to the boundary condition creation.

Clang format run on near-the-header lines.

Happy New Year

No need to pass the Node and then fetch its id.