Fixed StackOverflowError
Users can now only send messages to other users if they are on each other's friends list.
Removed SSL stuff for now
Added response to client when login password is incorrect
Merge remote-tracking branch 'origin/master'

Conflicts:
	src/main/scala/at/wambochat/backend/ChatClient.scala
	src/main/scala/at/wambochat/backend/ChatServer.scala
	src/test/scala/at/wambochat/test/ServerSpec.scala
Merge