- added methods direktUserAdd, direktuserDelete (for direkt User Zuordnung to le) to education/Lehreinheitgruppe_model
- added method getLvsByStudent to education/Lehrveranstaltung_model
- Added hasSequence = false to Benutzergruppe_model
- fixed typo in lehrveranstaltungDBML
- added functions for getting students and lecturers by lv
- added function for getting Studiengaenge By Studiensemester
- added function for getting Ausbildungssemester by Studiensemester and Studiengang