title: Newtonsoft Json.Net serialize JObject doesn't ignore nulls, even with the right settings
body: <p>I'm trying to serialize an object using Newtonsoft Json.Net.</p>
  
  <p>This object is an anonymous type filled with a lot of heterogenous things, mainly regular POCOs, but also some <code>JObject</code>s or <code>JArray</code>s.</p>
  
  <p>The thing is that when adding the <code>NullValueHandling</code> property to <code>NullValueHandling.Ignore</code>, every null property gets ignored, but only if it's part of a "regular" .Net object. Every null property inside a <code>JObject</code> or <code>JArray</code> remains.</p>
  
  <p>Here's a minimal example:</p>
  
  <pre><code>var jobj = JObject.FromObject(new Anything{
      x = 1,
      y = "bla",
      z = null
  });
  
  var poco = new Foo {
     foo1 = "bar",
     foo2 = null
  };
  
  var serialized = JsonConvert.SerializeObject(new {
      source1 = poco,
      source2 = jobj
  }, Newtonsoft.Json.Formatting.None, new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore});
  </code></pre>
  
  <p>Is there a simple way to ignore those null values as well ? Did I miss some setting option ? Or do I have to deal with it manually ?</p>