Reader only runs reconnection hook if connection is alive

[dlecocq]

While added is correctly dispatched when adding a new connection (dead or alive), in the case of Reader, the reconnected hook should only be dispatched if the added connection is alive.

[b4hand]

LGTM pending the explanation we had in person.

[dlecocq]

The Client class provides an added hook to indicate the discovery and addition of new connections, independent of their ability to establish a socket connection. The Reader class had previously assumed that the added connection was alive and attempted to subscribe to it.

The Client only dispatches reconnected directly if the connection object was previously dead and becomes alive.