mod_muc_markers: replace configurable multi-marker tracking with better system Now tracks a single marker, but automatically applies rules from the XEP about "higher" markers implying "lower" markers - i.e. "displayed" implies "received". Still, just a single marker is tracked and synthesized at all times (the one configured with muc_marker_name).

module:set_global();

local traceback = require "util.debug".traceback;

require"util.signal".signal(module:get_option_string(module.name, "SIGUSR1"), function ()
	module:log("info", "Received SIGUSR1, writing traceback");
	local f = io.open(prosody.paths.data.."/traceback.txt", "a+");
	f:write(traceback(), "\n");
	f:close();
end);