Merge pull request #772 from jidel/issue#771-missing_dunning

Fixed faulty generation of surrogate ids
Added help from patrick and corrected some typos
Merge pull request #774 from jidel/issue#768-second_dunning

Issue#768 second dunning
merge 065f468, optimise performance by only initialising states on
startup
optimise performance by only initialising states on startup
optimise performance by only initialising states on startup, general
performance, cleanup
Merge pull request #777 from davherrmann/issue#776

Issue#776: Optimise performance
Merge pull request #775 from henningmu/add_help

Added help from patrick and corrected some typos
Über die Student-Entity können nun direkt dessen TeachingMaterials
abgefragt werden
nicht benötigte inserts von BorrowedMaterials entfernt. Diese werden
beim Start der Anwendung automatisch erzeugt
Variablen des Studenten zu dessen BorrowedMaterials und Dunnings sowie
die entsprechenden getter/setter umbenannt
Performance optimiert
Merge pull request #779 from davvitt/issue#776-performanceOpt

Issue#776 performance opt
move help images to the right folder and rename them to contain no
umlauts or spaces
fixed references to images
fixed references to images
fix references to images
fix references to images
fix references to images
Merge pull request #781 from davherrmann/issue#780

Issue#780