ZonedDateTime for times before the epoch do not serialize correctly  #69

    public static void main(String[] args) throws Exception {
        ObjectMapper mapper = new ObjectMapper().registerModule(new JavaTimeModule());
        ZonedDateTime original = ZonedDateTime.parse("1959-04-13T05:05:38.599Z");
        String serialized = mapper.writeValueAsString(original);
        ZonedDateTime deserialized = mapper.readValue(serialized, ZonedDateTime.class);
        System.out.println(original);
        System.out.println(serialized);
        System.out.println(deserialized);
    }

1959-04-13T05:05:38.599Z
-338324062.599000000
1959-04-13T05:05:37.401Z[UTC]