Fix error logging on Remote

* JSON messages are now parsed in server.js
* Remote._handleMessage expects all messages to be objects rather
  than objects or strings
* Invalid responses from the server will now result in a log
  message that is not entirely vague
* Added Log.setEngine/getEngine. Use Log.setEngine(Log.engines.none)
  to silence logging

test/server-test.js

@@ -1,5 +1,7 @@
 'use strict';
+
 /* eslint-disable no-new */
+
 const _ = require('lodash');
 const assert = require('assert');
 const ws = require('ws');