fixes
Merge branch 'master' of https://github.com/LievenNuyts/SteveLievenEmin
...
Merge branch 'master' of https://github.com/LievenNuyts/SteveLievenEmin

Conflicts:
	Opdracht_1/src/model/MultipleChoiceExercise.java
	Opdracht_1/src/model/Quiz.java
ExerciseCatalog.java Updata:
	- added new methods to write to a file and read from a file