Saves ca. 35 unneeded includes (out of 260)
and 25s of compilation time (out of 149s).

The fmt library happily accepts std::string without
any conversions.

The LOGOG_COUT is equal to std::cout if the LOGOG_UNICODE
is *not* defined.

Main reason for modification is the getFlux function, which for
particular processes (ComponentTransport) relies on all solutions being
available.
This modification ripples through all of the code, especially through
the boundary conditions.
Modified `applyNaturalBC`, `preTimestep`, `integrate`, and `assemble`
functions.

Fixes multiple copyright messages in the doxygen docu.

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

This versions check if the PropertyVector is
assigned to the requested mesh item type and has
the required number of components.