title: Date in XLS sheet not parsing correctly
body: <p>I am trying to read a XLS file using 'XLSX' node-module with a column having dates. After parsing the file what I found is that the dates are of few dates back from that of the dates in the sheet.
  This is what I a doing.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>var workbook = XLSX.readFile(filePath);
  var grossPayoutSheet = workbook.Sheets[worksheets[1]];
  for (var i in grossPayoutSheet) {
      if (i[0] === "!") continue;
      var col = (!isNaN(parseInt(i.substring(1)))) ? i.substring(0,1) : i.substring(0,2);
      var row = (!isNaN(parseInt(i.substring(1)))) ? parseInt(i.substring(1)) : parseInt(i.substring(2));
      var value = grossPayoutSheet[i].v;
      if (row === 2) {
       var value = grossPayoutSheet[i].v;
       headers[col] = value.trim();
       continue;
      }
      if (row !== 1 &amp;&amp; !data[row]) {
       data[row] = {};
      } else if (row !== 1){
       data[row][headers[col]] = value;
      }
     }</code></pre>
  </div>
  </div>
  </p>
  
  <p>the value in the cell B3 is</p>
  
  <blockquote>
    <p>05/07/2017</p>
  </blockquote>
  
  <p>but after parsing the value is</p>
  
  <blockquote>
    <p>B3: { t: 'n', v: 42921, w: '42921' }</p>
  </blockquote>
  
  <p>I want the date in string format that is I want to change the cell format from 'n' to 's'</p>
  
  <p>Can anyone please me out with this?</p>