Use Title: meta instead of explicit <h1>

Author: tantek

css-animations-2/Overview.bs

@@ -1,5 +1,3 @@
-<h1>CSS Animations Level 2</h1>
-
 <style type="text/css">
   table.play-state-transitions {
     empty-cells: hide;
@@ -36,6 +34,7 @@
 </style>
 
 <pre class='metadata'>
+Title: CSS Animations Level 2
 Status: ED
 Work Status: Exploring
 Shortname: css-animations-2