Chat userlist logging for inital joining of chats. Doesn't work because the
chat-joined signal fires before libpurple gets the userlist. Still thinking
about how to fix it.
/*
* irssi - Implements several irssi features for Purple
* Copyright (C) 2005-2008 Gary Kramlich <grim@reaperworld.com>
* Copyright (C) 2006-2008 John Bailey <rekkanoryo@rekkanoryo.org>