title: LocalDateTime not serialized as a timestamp
body: <p>I'm using <code>jackson-datatype-jsr310</code> to support Java 8 time data types.</p>
  
  <p>I created a ObjectMapper like this: </p>
  
  <pre><code>ObjectMapper objectMapper = new ObjectMapper();
  objectMapper.configure(SerializationFeature.WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS, false);
  objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, true);
  objectMapper.registerModule(new JavaTimeModule());
  
  Foo foo = new Foo();
  LocalDateTime t = LocalDateTime.now();
  foo.setT1(Date.from(t.toInstant(ZoneOffset.UTC)));
  foo.setT2(Timestamp.valueOf(t));
  foo.setT3(t);
  
  System.out.println(objectMapper.writeValueAsString(foo));
  </code></pre>
  
  <p>And parsed a LocalDateTime then I got <code>[2016,12,21,15,53,57,178]</code> not <code>1482306837178</code></p>
  
  <p>Here is my test model class <code>Foo</code></p>
  
  <pre><code>public class Foo {
  
      private Date t1;
  
      private Timestamp t2;
  
      private LocalDateTime t3;
  
      // Getters &amp; Setters
  }
  </code></pre>
  
  <p>I see the question <a href="https://stackoverflow.com/questions/27951124/jackson-java-8-datetime-serialisation">Jackson Java 8 DateTime serialisation</a> and the problem owner get a serialized string like <code>1421261297.356000000</code>. I did't known how to get that. I'm using jackson 2.8.5 same with <code>datatype-jsr310</code>.</p>