title: moment.js - UTC gives wrong date
body: <p>Why does moment.js UTC always show the wrong date. For example from chrome's developer console:</p>
  
  <pre><code>moment(('07-18-2013')).utc().format("YYYY-MM-DD").toString()
  // or
  moment.utc(new Date('07-18-2013')).format("YYYY-MM-DD").toString()
  </code></pre>
  
  <p>Both of them will return <strong>"2013-07-17"</strong> why is it returning <strong>17th</strong> instead of <strong>18th</strong>, that was passed in.</p>
  
  <p>But if I use momentjs without the utc: </p>
  
  <pre><code>moment(new Date('07-18-2013')).format("YYYY-MM-DD").toString()
  </code></pre>
  
  <p>I get back <strong>"2013-07-18"</strong> which is what I also expect when using moment.js UTC.</p>
  
  <p>Does this mean we cannot get the correct date when using moment.js UTC?</p>