master: networking: Added application-level protocol for closing the connection
    -- when the game finished (lost/victory), tear down client-thread on server side
       gracefully; tear down integration-poller gracefully on client side
    -- handled client abnormal escape gracefully relying on ClientCommuncationLoop#cleanup,
       logging all error info asynchronously in server-side application driver
    -- added new user command type CMD_GAMEEOF_ACK in TsuUserEvent; use
       TsuNetworkingIntegrationMessage {null, null, null, null} to denote game EOF from
       the server side
    -- added victory/lost temporary screen stub
    -- added TsuINetworkableErrorHandling interface forcing client/server to implement
    -- TODO: handle abnormal server tear-down in TsuNetworkingManagerClient, asynchronously
       and gracefully in client-side application driver