ensure that hidden tags are not shown in any of BibSonomy's exports

[Robert Jäschke]

E.g., have a look at

http://www.bibsonomy.org/bibtex/26ffcc0d793bbe53bf6ed17f9d929846e/jaeschke

or

http://www.bibsonomy.org/bib/bibtex/26ffcc0d793bbe53bf6ed17f9d929846e/jaeschke

where the keyword "sys:hidden:alexandria" is contained in the output. even if you are not logged in.

[Daniel Zoller]

i think that this is fixed