Server sockets made non-blocking

Server sockets are now non-blocking by default,the client login details
are now taken and handled in Server::receive().
Did some cleanup and dealt with g++ warnings.
Changed the default users on members.dat to non-human names.
These are the new memberes and their passwords:
raptor:raptorpass
trex:trexpass
firefly:fireflypass
albatross:albatrosspass
Default members changed
Seperated Database functionality into class UserDatabase

User passwords are now hash supported , the function pwd_hash() now
returns the plaintext password , it's implementation could be changed to
store hashed passwords