By default, a server is now sending to its clients the client URLs
of all servers in the cluster. This allows clients to be able
to reconnect to any server in the cluster even if those clients
were not configured with the list of servers in the cluster.
However, there may be cases where it would make sense to disable
this feature. This now can be done with this option/command line
parameter.
Resolves#322
If the server was started with a cluster section in a configuration
file and one would want to override the routes (using `-routes`) the
server would complain that you need to use `-cluster`. Adding
an override of cluster would not work, server would still complain.
Trying to override simply the cluster listen info (without override
of routes) would also not work.
