Fixed problem with mutiple printing of the same subject category. Thanks to Kam-ming Ku for reporting the problem.  Also, removed trailing whitespace.
Fixed problem with mutiple printing of the same subject category.
Thanks to Kam-ming Ku for reporting the problem.  Also, removed
trailing whitespace.

tiborsimko/invenio,tiborsimko/invenio,inveniosoftware/invenio,inveniosoftware/invenio