Improve labrad doc string for 'Connection Info' setting.

[maffoo]

Setting info in pylabrad now looks like this:

In [3]: cxn.manager.connection_info
Out[3]: 
LabRAD Setting: "Manager" >> "Connection Info" (ID=10000)

Get information about connected servers and clients.

Returns a list of clusters, one for each connection. Each cluster
contains the following elements:
 - id: The connection id (pass to `Close Connection` to kill connection.
 - name: The connection name.
 - is_server: Boolean indicating if this is a server (true) or client (false).
 - server_requests: Number of requests received by server (meaningless for clients).
 - server_replies: Number of replies sent by server (meaningless for clients).
 - client_requests: Number of requests sent by client or server.
 - client_replies: Number of replies received by client or server.
 - messages_sent: Number of messages sent by client or server.
 - messages_received: Number of messages received by client or server.

Accepts:
    _

Returns:
    *(wsbwwwwww)

Fixes #62

@ejeffrey

[ejeffrey]

LGTM