title: serverList() only returns 100 results
body: <p>I'm trying to write a bit of code to inventory our OpenStack deployment, and I've run into an issue where <code>serverList()</code> only ever returns 100 results instead of the 600+ I'm expecting. I've reviewed the documentation and a bit of the source, and as far as I can tell there's no reason that this should be happening as the PaginatedIterator should be doing its pagination transparently.</p>
  
  <p>There are no errors or warning either generated in my code, or logged on my controller [that I can find]. I am using php-opencloud v1.12 via composer.</p>
  
  <pre><code>use OpenCloud\OpenStack;
  $client = new OpenStack('http://1.2.3.4:5000/v2.0/', array(
      'username'  =&gt; 'admin',
      'password'  =&gt; 'hunter2',
      'tenantName'=&gt; 'admin',
  ));
  $service = $client-&gt;computeService('nova', 'RegionOne');
  
  $stmt = $dbh-&gt;prepare('INSERT INTO servers VALUES (?,?)');
  /* foreach($service-&gt;serverList() as $server) {
      $stmt-&gt;execute([$server-&gt;id, $server-&gt;name]);
  } // neither method works */
  $list = $service-&gt;serverList();
  while( $list-&gt;valid() ) {
      $server = $list-&gt;current();
      $stmt-&gt;execute([$server-&gt;id, $server-&gt;name]);
      $list-&gt;next();
  }
  echo "\n";
  var_dump($dbh-&gt;query('SELECT * FROM servers')-&gt;fetchAll(PDO::FETCH_ASSOC));
  </code></pre>