Update default value of sockjs_url to point to 0.3 client

Author: igorw

src/sockjs.coffee

@@ -138,7 +138,7 @@ class Server extends events.EventEmitter
             heartbeat_delay: 25000
             disconnect_delay: 5000
             log: (severity, line) -> console.log(line)
-            sockjs_url: 'http://cdn.sockjs.org/sockjs-0.2.min.js'
+            sockjs_url: 'http://cdn.sockjs.org/sockjs-0.3.min.js'
         if user_options
             utils.objectExtend(@options, user_options)