manager / Synchronize terms in de and de-informal

This now gives proper files and line numbers for errors

made necessary by PR#254 which adds content below these notes.

/ fix several typos / Fixes FS#2821

This reverts commit d6d85509.

I guess it was a bit too early to think straight :-/

also made it more secure against copy'n'paste

The refshow configuration option wasn't used as described anymore
already in the latest release and after the introduction of the media
usage index the parameter is also no longer relevant for internal
optimization. The only place where it was still used is the no longer
used search_references()-function which is removed here, too.

The refshow configuration option wasn't used as described anymore
already in the latest release and after the introduction of the media
usage index the parameter is also no longer relevant for internal
optimization. The only place where it was still used is the no longer
used search_references()-function which is removed here, too.

This makes it possible to safely overwrite ini replacements from within
any less file