Use Title: meta instead of explicit <h1>

Author: tantek

css-animations-1/Overview.bs

@@ -1,5 +1,3 @@
-<h1>CSS Animations Level 1</h1>
-
 <style type="text/css">
   table.event-handlers {
     border-collapse: collapse;
@@ -14,6 +12,7 @@
 </style>
 
 <pre class='metadata'>
+Title: CSS Animations Level 1
 Status: ED
 Work Status: Refining
 Shortname: css-animations