title: strtolower() for unicode/multibyte strings
body: <p>I have some text in a non-English/foreign language in my page,
  but when I try to make it lowercase, it characters are converted into black diamonds containing question marks.</p>
  <pre><code>$a = &quot;Երկիր Ավելացնել&quot;;
  echo $b = strtolower($a);
  //returns  ����� ���������
  </code></pre>
  <p>I've set my charset in a metatag, but this didn't fix it.</p>
  <pre><code>&lt;meta http-equiv=&quot;Content-Type&quot; content=&quot;text/html; charset=utf-8&quot; /&gt;
  </code></pre>
  <p>What can I do to convert my string to lowercase without corrupting it?</p>