Merge remote-tracking branch 'origin/milestone-02' into certificate-service

# Conflicts:
#	commons/src/main/java/cz/muni/fi/commons/domain/BaseEntity.java
#	core/src/main/java/cz/muni/fi/core/data/mapper/CourseMapper.java
#	core/src/main/java/cz/muni/fi/core/data/model/Course.java
#	core/src/main/java/cz/muni/fi/core/data/model/Exercise.java
#	core/src/main/java/cz/muni/fi/core/data/model/Lecture.java
#	core/src/main/java/cz/muni/fi/core/data/repository/CourseRepository.java
#	core/src/main/java/cz/muni/fi/core/data/repository/LectureRepository.java
#	core/src/main/java/cz/muni/fi/core/facade/CourseFacade.java
#	core/src/main/java/cz/muni/fi/core/rest/CourseRestController.java
#	core/src/main/java/cz/muni/fi/core/service/CourseService.java
#	core/src/test/java/cz/muni/fi/core/facade/CourseFacadeTest.java
#	core/src/test/java/cz/muni/fi/core/facade/ExerciseFacadeTest.java
#	core/src/test/java/cz/muni/fi/core/facade/LectureFacadeTest.java
#	core/src/test/java/cz/muni/fi/core/factory/TestDataFactory.java
#	core/src/test/java/cz/muni/fi/core/rest/CourseRestControllerTest.java
#	core/src/test/java/cz/muni/fi/core/rest/ExerciseRestControllerTest.java
#	core/src/test/java/cz/muni/fi/core/rest/LectureRestControllerTest.java
#	core/src/test/java/cz/muni/fi/core/service/CourseServiceTest.java
#	core/src/test/java/cz/muni/fi/core/service/ExerciseServiceTest.java
#	core/src/test/java/cz/muni/fi/core/service/LectureServiceTest.java