title: POCO HTMLForm How to read input form element with name like invoice[items][1]
body: <p>If my HTML form inputs are like this:</p>
  
  <pre><code>&lt;input name='invoice[items][1]' /&gt;
  &lt;input name='invoice[items][2]' /&gt;
  &lt;input name='invoice[payments][1]' /&gt;
  &lt;input name='invoice[payments][2]' /&gt;
  </code></pre>
  
  <p>In PHP, I can handle this kind of post or get data like this:</p>
  
  <pre><code>$items = $_POST['invoice']['items'];
  $payments=$_POST['invoice']['payments'];
  </code></pre>
  
  <p>How can I handle this kind on inputs in Poco Library?</p>