`disableListen` is unnecessary

[wearhere]

The server only starts listening if Arena is loaded directly i.e. in standalone mode.

When mounting Arena into another server, the client would not be calling run, so run does not need to take an option that disables listening (and I'm not sure why you would call run if you didn't want to listen).

[p3x-robot]

we use arena in an app so it is necessary... :) we don't wanto to listen on another ports, besides it uses spdy....