title: TCPDF HTML with Special Characters displays empty PDF file
body: <p>I am using TCPDF Library Version: 5.9.011. I am trying to execute HTML layout as PDF. For which I tried with example provide with the <a href="http://www.tecnick.com/pagefiles/tcpdf/example_006.phps">site</a></p>
  
  <pre><code>$html = '&lt;h1&gt;HTML Example&lt;/h1&gt;
  &lt;h2&gt;List&lt;/h2&gt;
  Some special characters: &amp;lt; € &amp;euro; &amp;#8364; &amp;amp; è &amp;egrave; &amp;copy; &amp;gt; \\slash \\\\double-slash \\\\\\triple-slash
  ';
  // output the HTML content
  $pdf-&gt;writeHTML($html, true, false, true, false, '');
  
  //Close and output PDF document
  $pdf-&gt;Output('example_006.pdf', 'I');
  </code></pre>
  
  <p>Apparently found that generated PDF only default header and footer with middle content blank.</p>
  
  <p>However if I remove special characters like:</p>
  
  <pre><code>$html = '&lt;h1&gt;HTML Example&lt;/h1&gt;
  &lt;h2&gt;List&lt;/h2&gt;
  Some special characters:
  ';
  </code></pre>
  
  <p>PDF gets its middle content as specified in <code>$html</code></p>