Add <audio> and <video> tests to demo. Fix necolas#21

Author: necolas

demo.html

@@ -80,6 +80,11 @@ <h1>Text-level semantics</h1>
 
         <h1>Embedded content</h1>
 
+        <h3>audio</h3>
+
+        <audio controls></audio>
+        <audio></audio>
+
         <h3>img</h3>
 
         <img src="http://placekitten.com/100/100" alt="">
@@ -89,6 +94,11 @@ <h3>svg</h3>
 
         <svg style="width:100px; height:100px;"><circle cx="100" cy="100" r="100" fill="#ff0000"></svg>        
 
+        <h3>video</h3>
+
+        <video controls></video>
+        <video></video>
+
         <h1>Grouping content</h1>
 
         <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et m.</p>