added helper methods for creating schoolyears
added JUnit test for LendingViewModel
Merge pull request #687 from davherrmann/issue#215

Issue#215
Fixed warning window of settings tab
Merge pull request #689 from jidel/issue#686

Fixed warning window of settings tab
Added "testFullImport" and "testDeltaImport".
It tests if full import and delta import store the entities correctly.
Added "updateStudentByImport" test method. 
Tests if a student is replaced correctly with an imported student having
the same id.
Merge pull request #691 from B3nRa/#649

#649: add JUnit tests for StudentInformationViewModel
bind Properties as lazy singleton
change modifiers of States from private to public final
Deleted PDFOrderList.
It is not needed in our program. (Was used by previous group)
added helper methods for Entity instantiation
added test methods for state testing
Merge pull request #693 from B3nRa/#652

Deleted PDFOrderList.
added cascading options
fixed Logger initialisation
use a category when creating TeachingMaterial
added further tests
simplified test
added helper methods for creating a user