title: rich:dataTable getting the total from filterBy columns
body: <p>I have a rich datatable with columns that I can filter.</p>
  
  <pre><code>&lt;!-- Data table with filters --&gt;
  &lt;h:form&gt;
  &lt;rich:dataTable value="#{sessionScope.paymentsBean.payments}" var="payment"
     id="table"&gt;
     &lt;rich:column filterBy="#{sessionScope.payment.invoice}" filterEvent="onkeyup"&gt;
        &lt;f:facet name="header"&gt;Invoice&lt;/f:facet&gt;
        &lt;h:outputText value="#{sessionScope.payment.invoice}" /&gt;
     &lt;/rich:column&gt;
     &lt;rich:column filterBy="#{sessionScope.payment.description}" filterEvent="onkeyup"&gt;
        &lt;f:facet name="header"&gt;Description&lt;/f:facet&gt;
        &lt;h:outputText value="#{sessionScope.payment.description}" /&gt;
     &lt;/rich:column&gt;
     &lt;rich:column filterBy="#{sessionScope.payment.amount}" filterEvent="onkeyup"&gt;
        &lt;f:facet name="header"&gt;Amount&lt;/f:facet&gt;
        &lt;h:outputText value="#{sessionScope.payment.amount}" /&gt;
      &lt;/rich:column&gt;
  &lt;/rich:dataTable&gt;
  &lt;/h:form&gt;
  
  &lt;!-- Total --&gt;
  &lt;h:outputText id="total" value="#{sessionScope.paymentsBean.total}" &gt;
      &lt;f:convertNumber maxFractionDigits="2" type="currency" currencySymbol="$"/&gt;
  &lt;/h:outputText&gt;
  </code></pre>
  
  <p>For the total, I can sum all the amounts in sessionScope.paymentsBean.payments to get the total. Which is $355.00 in the following example.</p>
  
  <pre><code>Invoice     Description     Amount
  1           Cash            $5.00
  2           Visa            $50.00
  3           Visa            $100.00
  4           MasterCard      $200.00 
  
  Total: $355.00
  </code></pre>
  
  <p>However, if I filter by "Visa", the table and total would look like:</p>
  
  <pre><code>Invoice     Description     Amount
  2           Visa            $50.00
  3           Visa            $100.00
  
  Total: $355.00
  </code></pre>
  
  <p>The total should be $150 but getTotal() doesn't know about the filterBy data.
  Is there a way to dynamically calculate the total based on the filterBy criteria from the rich:datatable?</p>