verify: move manifest verification to its own function
This makes verify more modular, making it easier for extensions to extend.
{header}
<title>{repo|escape}: tags</title>
<link rel="alternate" type="application/atom+xml"
href="{url|urlescape}atom-tags" title="Atom feed for {repo|escape}: tags">
<link rel="alternate" type="application/rss+xml"
href="{url|urlescape}rss-tags" title="RSS feed for {repo|escape}: tags">
</head>
<body>
<div class="buttons">
<a href="{url|urlescape}log{sessionvars%urlparameter}">changelog</a>
<a href="{url|urlescape}shortlog{sessionvars%urlparameter}">shortlog</a>
<a href="{url|urlescape}graph{sessionvars%urlparameter}">graph</a>
<a href="{url|urlescape}branches{sessionvars%urlparameter}">branches</a>
<a href="{url|urlescape}file{sessionvars%urlparameter}">files</a>
<a href="{url|urlescape}help{sessionvars%urlparameter}">help</a>
<a type="application/rss+xml" href="{url|urlescape}rss-tags">rss</a>
<a type="application/atom+xml" href="{url|urlescape}atom-tags">atom</a>
</div>
<h2><a href="/">Mercurial</a> {pathdef%breadcrumb} / tags</h2>
<ul id="tagEntries">
{entries%tagentry}
</ul>
{footer}