fix for BIESt #957

app/controllers/news.php

app/controllers/plugin_controller.php

app/controllers/studip_controller.php

app/views/calendar/contentbox/display.php

app/views/news/display.php

lib/bootstrap.php

lib/calendar/CalendarColumn.class.php

lib/classes/Assets.class.php

lib/classes/Avatar.class.php

lib/classes/Log.php

lib/classes/NotificationCenter.class.php

lib/classes/PageLayout.php

lib/classes/RangeConfig.class.php

lib/classes/Request.class.php

lib/classes/SemBrowse.class.php

lib/classes/SkipLinks.php

lib/classes/Smiley.php

lib/classes/StudipPDO.class.php

lib/classes/StudipPDOStatement.php

lib/classes/URLHelper.php