Move HTML5 Shiv after CSS.

Per usage notes at <https://github.com/aFarkas/html5shiv/blob/master/readme.md>.

default.html5

@@ -12,9 +12,6 @@ $if(date-meta)$
 $endif$
   <title>$if(title-prefix)$$title-prefix$ - $endif$$pagetitle$</title>
   <style type="text/css">code{white-space: pre;}</style>
-  <!--[if lt IE 9]>
-    <script src="//cdnjs.cloudflare.com/ajax/libs/html5shiv/3.7.3/html5shiv-printshiv.min.js"></script>
-  <![endif]-->
 $if(quotes)$
   <style type="text/css">q { quotes: "“" "”" "‘" "’"; }</style>
 $endif$
@@ -29,6 +26,9 @@ $endfor$
 $if(math)$
   $math$
 $endif$
+  <!--[if lt IE 9]>
+    <script src="//cdnjs.cloudflare.com/ajax/libs/html5shiv/3.7.3/html5shiv-printshiv.min.js"></script>
+  <![endif]-->
 $for(header-includes)$
   $header-includes$
 $endfor$