fix for BIESt #971

app/controllers/admin/courses.php

app/controllers/my_courses.php

app/controllers/plugin_controller.php

app/controllers/studip_controller.php

app/views/admin/courses/_course.php

app/views/admin/courses/courses.php

app/views/my_courses/_dozent.php

app/views/my_studygroups/_course.php

lib/classes/AdminCourseFilter.class.php

lib/classes/MyRealmModel.php

lib/classes/Request.class.php

lib/classes/SemClass.class.php

lib/classes/Seminar.class.php

lib/classes/SeminarCategories.class.php

lib/classes/SkipLinks.php

lib/classes/WidgetContainer.php

lib/classes/sidebar/SearchWidget.php

lib/classes/sidebar/SelectWidget.php

lib/dates.inc.php

lib/functions.php