Merge remote branch 'origin/feature/6882_export_unitfactory'
Re #6804. Add a missing test.
Re #6804. Remedy cppcheck warnings.
Re #6804. Remove unused variables and thus warning.
Re #6804. Remove strange categorization.
Re #6804. cppcheck warning.
Re #6804. Remove a comment that I don't want to see every time.
Re #6804. Fix indentation. No code changes.
Re #6804. Remove unused variable.
Re #6804. Remove deprecated header and its usage.
Merge branch 'feature/6804_warnings' into develop