Add error handling for ECONNREFUSED to the cli tool

[ryugi]

Right now we get an ugly stacktrace if the cli server's not running and you try to run timi:

events.js:141
      throw er; // Unhandled 'error' event
      ^

Error: connect ECONNREFUSED 127.0.0.1:5097
    at Object.exports._errnoException (util.js:870:11)
    at exports._exceptionWithHostPort (util.js:893:20)
    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1063:14)