Small changes to the logging.
Further improvements. configureConnections is now public - needed for passing UserConnection across thread boundries. I've replaced shared_ptr<QTcpSocket> with naked pointer - I don't know how would smart pointer behave when UserConnectin object was sent with signals, also I needed to use deleteLater on socket for safe deleting.
I've added simple methods for handling requests. Adding new user to trading server is full implemented.
Full implementation of passing user connection to appropriate trading server.
Partial implementation of login mechanism. I've also changed processMessageFrom - before reading each message it check whether user is still present on server.