title: converting string map to json using jsoncpp
body: <p>I am using jsoncpp, is there a way to put a map in Json::Value ?</p>
  
  <p>I understand I can extract keys one by one and put them in the Json::Value. but is there a more graceful way  ? for example in the C# counter part NewtonSoft json api</p>
  
  <p>I would do </p>
  
  <pre><code>      String json = JsonConvert.SerializeObject(cmdDict);   
  </code></pre>