fix(lib/index.js) return auth.success

Next step would not execute because no function(socket, next) was returned in case of successful verification in the 'one roundtrip' (handshake) approach.
Returning auth.success instead of just executing it solves this.

Fixes #51

lib/index.js

@@ -144,7 +144,7 @@ function authorize(options, onConnection) {
 
       data.decoded_token = decoded;
 
-      auth.success(data, accept);
+      return auth.success(data, accept);
     });
   };
 }