ENH: Add default constructor option for JacksonBodyAdapter() with reasonable defaults

[rbygrave]

  public JacksonBodyAdapter() {
    this.mapper = new ObjectMapper()
      .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
      .configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false)
      .configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false)
      .setSerializationInclusion(JsonInclude.Include.NON_EMPTY);
  }