added thread safe queue wrapper
thread template now allows params
finally got the communication right

- interrupting threads works
- client/server have main thread that checks state of data threads
- they also wait for external shutdown requests (done by deleting the
  CommunicationController instance)
- moved connection accepting to seperate thread
- server is now able to handle multiple connections (there is no extra
  data queue per client connection -> data is sent to all clients)
- client is doing retry when connection lost
- cleaned up debugging outputs