title: Add one month to a date in Velocity template
body: <p>I have a Velocity template with variable <code>$facet.name</code> holding a date. Now I want to add one month to this date. I'm doing it as following:</p>
  
  <pre><code>#set( $cal = $Calendar.getInstance.setTime($facet.name) )
  $cal
  $cal.add($Calendar.MONTH,1)
  $cal.getTime.toString
  </code></pre>
  
  <p>Last 3 rows are evaluated as is: I got</p>
  
  <pre><code>$cal
  $cal.add($Calendar.MONTH,1)
  $cal.getTime.toString
  </code></pre>
  
  <p>as output.
  How should I do it correct way?</p>