changed profile mapping of student and teaching material
--> now they have a list of ProfileTypes

added lazy loading to entitie relationships
changed profile list to profile set
Merge pull request #42 from davvitt/changeEntityClasses

changed profile mapping of student and teaching material
init profiles and teachingmaterials set as HashSet by default
Merge pull request #44 from davvitt/changeEntityClasses

init Set in Profile and TeachingMaterial as HashSet by default
added nested Builder + associated tests
Merge pull request #47 from davherrmann/issue#36

added example Builder for Student + associated tests
added builder to all entitie classes
Merge pull request #52 from davvitt/issue#36-builder

added builders to all entity classes
added equals() and hashCode() method to all entities
Merge pull request #53 from davvitt/issue#46-equals&hash

added equals() and hashCode() methods to all entities
Merge branch 'develop' of https://github.com/HumBuch/HumBuch.git into upstream/develop
Merge branch 'upstream/develop' into developNew
Minimal adjustments to some screens
Merge branch 'developNew' of https://github.com/henningmu/HumBuch.git
into developNew

Conflicts:
	src/main/java/de/dhbw/humbuch/ui/screens/ManageBooksScreen.java