histedit: move locks into state
Allow action functions to control the locks. This is necessary for
an implementation of x/exec or similar.
<item>
<title>{bookmark|escape}</title>
<link>{urlbase}{url|urlescape}rev/{node|short}</link>
<description><![CDATA[{bookmark|strip|escape|addbreaks}]]></description>
<pubDate>{date|rfc822date}</pubDate>
</item>