replaced sysouts with assertTrues
added rollbacks to all methods

new methods:

makeFriends
unfriend
UserDTO -> changed REALITION_FRIENDS to enum RELATIONSHIPS with value
FRIENDS

OrientDBDao implemented methods:

- findUser
- findFriends
- findFriendsOfFriends
- makeFriends
- unfriend

Included test-cases for the new mehtods of OrientDBDao
Merge branch 'master' of git@github.com:vimaier/nosql_dbs.git

Conflicts:
	The SocialNetwork/src/main/java/de/graphdb/db/orientdb/OrientDbDao.java
	The SocialNetwork/src/main/java/de/graphdb/dto/UserDTO.java
refactored again field 'forname' to 'forename'