Fixes multiple copyright messages in the doxygen docu.

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

The default impl., which is not doing anything, is error prone,
because passing an object of not matrix type, e.g. std::unique_ptr<PETScVector>,
the default impl. will be taken.

Clang format run on near-the-header lines.

Happy New Year

to set a local vector of a processor from the global one.