added TabChangeListener to Accordion
implemented toString()
implemented method to incdicate if the student has unreceived
BorrowedMaterials
LendingView is using live data.
LendingViewModel sets BorrowedMaterials as received.
Merge branch 'upstream/develop' into issue#82-receivedFlagInLendingView

Conflicts:
	src/main/java/de/dhbw/humbuch/view/LendingView.java
	src/main/java/de/dhbw/humbuch/view/components/EnterDataComponent.java
removed database password
Merge pull request #179 from davvitt/issue#82-receivedFlagInLendingView

Issue#82 received flag in lending view