title: ColumnToggle: hide some columns
body: <p>I'm working with primefaces 5.0 and i created one Primefaces:Datatable with Column:ColumnToggle but i need define initial columns to display.
  How to hide some columns initially?
  With property toggleable="false" i define that column not toggleable. Don't exist one property that defines initial columns?</p>
  
  <pre><code>&lt;p:datatable ...&gt;
      &lt;f:facet name="header"&gt;
            &lt;p:commandButton id="toggler" type="button" value="Data" icon="ui-icon-calculator" /&gt;
            &lt;p:columnToggler datasource="itemsDT" trigger="toggler" /&gt;
      &lt;/f:facet&gt;
      ...
  &lt;/p:datatable&gt;
  </code></pre>