title: Tabulator: Force update of cells if the value is constant but the formatted value not (datetimediff)
body: <p>I currently face this problem</p>
  
  <p>I'm using a column formatted with the build in <code>datetimediff</code> formatter to display the <strong>last seen</strong> timestamp from remote devices formatted in a humanized way i.e. <code>1 minute ago</code> or <code>2 days ago</code></p>
  
  <p>The problem is that in this case the value of the tabledata is constant but the displayed value (returned by the formatter) change over time. (lastSeen - Date.now())</p>
  
  <p>The question is how to update the displayed value if the raw data is constant (i.e. every minute). </p>
  
  <p>I tried to update the values with <code>updateData</code> which works as expected when the values differ (the remote device is active) but if the remote device is offline and the value is constant the formatted value does not update as it should.</p>
  
  <p>I assume that tabulator stops the update process before the formatter callback when the value sent by <code>updateData</code>is the same as the existing one.</p>
  
  <p>Is there a way to force tabulator to perform a update through the formatter? Or make tabulator perform the check after the formatter comparing the display values instead the raw data?</p>
  
  <p>Thank you for your help.</p>