title: Countdown.js adding one extra month out of nowhere?
body: <p>Why does the following not work?</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html lang="en"&gt;
  &lt;head&gt;
      &lt;meta charset="UTF-8"&gt;
      &lt;title&gt;Example&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;h2 class="counter"&gt;
          Time to start: &lt;span id="counter-text"&gt;&lt;/span&gt;
      &lt;/h2&gt;
  
      &lt;script src="../js/countdown.js"&gt;&lt;/script&gt;
      &lt;script src="../js/main.js"&gt;&lt;/script&gt;
  &lt;/body&gt;
  </code></pre>
  
  <p></p>
  
  <p>Main.js:</p>
  
  <pre><code>function setTime() {
      var timeUntil = countdown(Date.now(), new Date(2016, 12, 3, 18, 0, 0, 0));
  
      document.getElementById('counter-text').textContent = timeUntil;
  }
  
  setInterval(setTime, 200);
  </code></pre>
  
  <p>It represents it as if it was until 3rd of January, not December. Same happens if I try November, October... always one month ahead.</p>
  
  <p>As of today, it outputs: </p>
  
  <p><strong>Time to start: 85 days, 5 hours, 46 minutes and 47 seconds</strong></p>
  
  <p>instead of expected</p>
  
  <p><strong>Time to start: 54 days, 5 hours, 46 minutes and 47 seconds</strong></p>