Autodetect user timezone using Javascript, this makes the Preferences code a bit more complicated in terms of interaction between default/parse/is_default/build/process/etc, but it should work as intended now
<% formatter = prefs['formatter'] %>
<div id="lines">
% if formatter.html_fixedwidth :
<pre>
% endif
% for line, html in lines:
<a href="${h.build_url(urls.channel_link, channel=channel, timestamp=line.timestamp)}#${h.utc_timestamp(line.timestamp)}" id="${h.utc_timestamp(line.timestamp)}">»» </a>${html}
% endfor
% if formatter.html_fixedwidth :
</pre>
% endif
</div>