Fixed SSLListener failing to accept SSLSockets properly (not setting the descriptor properly).
TcpSocket::receive_raw and SSLSocket::receive_raw now behave the same, rather than SSLSocket acting more like Socket::receive_all.
Documented specific return values from Socket::receive_all().
Socket::receive_all now returns WouldBlock if the socket is in blocking mode and the first read returns no data, so it doesn't behave like a blocking socket.
Disabled copying/moving of sockets. Copying shouldn't have been enabled, but might add move constructors in the future.
Added Socket::disconnect, which internally just calls close_socket, to allow for protocol-specific disconnect sequences in the future (WebSockets).