- The SocketClient supports specifying remote hostname
in constructor or when calling connect.

- The patch changes SocketClient to only support the latter i.e:

  SocketClient s();
  s->init();
  s->bind(local_hostname, local_port);
  s->connect(server_hostname, server_port);

- This makes it possible to remove SocketClient's duplicate
knowledge of remote hostname, port and resolved adress plus the
setter/getters for those. These parameters are already known
by the Transporter or the mgmapi which use SocketClient.

 - The resolve of remote hosts adress is now done in connect() instead of init()

 - Remove some convoluted usage of SocketClient as the carrier of parameters
to TransporterRegistry::connect_mgmd()

 - Remove the unimplemented close() function.