Fixing #107. Apparently some signal handlers were getting connected twice (double import?) and thus saving a forum post would cause 2 email notifications to go out to the post topic's subscribers. Use the dispatch_uid parameter in the connect call to work around this issue.

Dear {{ to_name }},

Your friend, {{ sender_name }}, wanted to send you a link to an 
interesting story found on {{ site_name }}.

{{ story_title|safe }}
http://{{ site_url }}{{ story_link }}

Thanks!
http://{{ site_url}}