title: EXSLT date:add function has unexpected results
body: <p>I want to get tomorrows date using exslt date.</p>
  
  <p><code>date:date()</code> returns todays date ('2014-01-23') and if I am adding 1 day ('P1D'), I expect it to be tomorrow ('2014-01-24'). But instead the result of</p>
  
  <pre><code>&lt;xsl:value-of select="date:add(date:date(), 'P1D')"/&gt;
  </code></pre>
  
  <p>is '2014-01-23T23:00:00Z'.</p>