bug fixed Timetable_addActivity_Test

tests laufen durch
Merge branch 'master' of https://github.com/ironmen-swp/timetable

Conflicts:
	src/main/java/timetable/tests/Timetable_addActivity_Test.java
Merge branch 'master' of https://github.com/ironmen-swp/timetable

Conflicts:
	src/main/java/timetable/tests/Timetable_addActivity_Test.java