Changes

* Even though Bibtex is not encoding-aware at all, it does allows special (8-bit) characters. So there is no need for ugly constructs like \"a (for ä) or \'e (for é). The one exception is within author family names, because those are handled especiallyspecially, both for sorting and for generating so-called 'short tags'. For the same reasons, one must also avoid using non-ascii characters in the bibtex citation reference labels.