title: export p:datatable to excel in PrimeFaces
body: <p>I want to export a datatable to excel.
  I can not display the title of the datatable in excel.</p>
  
  <pre><code>&lt;p:commandLink ajax="false"&gt;
    &lt;h:outputLabel value="Excel"/&gt;
      &lt;p:dataExporter type="xls" 
           target="idColPlanCompteM61Export" 
           fileName="PlanCompteM61" 
           postProcessor="#{planCompteM61ManagerBean.postProcessXLS}"/&gt;
  &lt;/p:commandLink&gt;
  
  &lt;p:dataTable id="idColPlanCompteM61Export" var="ligne" value="#{planCompteM61ManagerBean.listeColPlanCompteM61Filtree}"&gt;
              &lt;f:facet name="header"&gt;
                     &lt;div class="printTitrePosition"&gt;
                             &lt;h:outputText value="Plan de compte M61"/&gt;
                     &lt;/div&gt;
              &lt;/f:facet&gt;
              ...
              ... 
  </code></pre>
  
  <p>No title is displayed</p>