title: how dompdf supports php7
body: <p>I used older version of dompdf in a project about 5 years ago. Now I just downloaded 0.8.0 (<a href="https://github.com/dompdf/dompdf/releases" rel="nofollow noreferrer">https://github.com/dompdf/dompdf/releases</a><a href="https://github.com/dompdf/dompdf/releases" rel="nofollow noreferrer">link</a>) version, and its release note says "Improves compatibility with PHP 7.1". But for demo usage, it has php5.x "use" style as "use Dompdf\Dompdf;" that throw error on PHP 7. What is appropriate method to use dompdf on php7?  </p>