Adding random_messages mod with simple messages

- Random messages mod by @arsdragonfly (http://github.com/arsdragonfly)
  has been added to the server mods.

mods/random_messages/README.txt

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+RandomMessages mod by arsdragonfly.
+Put your messages in (world directory)/random_messages,1 message per line.
+Messages can be all kinds of hints, mod usage, etc.
+In minetest.conf, random_messages_interval decides how often a message is sent.
+Released under CC0.
+Special thanks to:
+Michael Rasmussen (michael@jamhome.us)
+Enjoy it! ^_^
+arsdragonfly@gmail.com
+6/19/2013

mods/random_messages/depends.txt

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+default

mods/random_messages/init.lua

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+--[[
+RandomMessages mod by arsdragonfly.
+arsdragonfly@gmail.com
+6/19/2013
+--]]
+--Time between two subsequent messages.
+local MESSAGE_INTERVAL = 0 
+
+math.randomseed(os.time())
+
+random_messages = {}
+random_messages.messages = {} --This table contains all messages.
+
+function random_messages.initialize() --Set the interval in minetest.conf.
+	minetest.setting_set("random_messages_interval",120)
+	minetest.setting_save();
+	return 120 
+end
+
+function random_messages.set_interval() --Read the interval from minetest.conf(set it if it doesn'st exist)
+	MESSAGE_INTERVAL = tonumber(minetest.setting_get("random_messages_interval")) or random_messages.initialize()
+end
+
+function random_messages.read_messages()
+	local line_number = 1
+	local input = io.open(minetest.get_worldpath().."/random_messages","r")
+	if not input then
+		local output = io.open(minetest.get_worldpath().."/random_messages","w")
+		output:write("Blame the server admin! He/She has probably not edited the random messages yet.\n")
+		output:write("Tell your dumb admin that this line is in (worldpath)/random_messages \n")
+		io.close(output)
+		input = io.open(minetest.get_worldpath().."/random_messages","r")
+	end
+	for line in input:lines() do
+		random_messages.messages[line_number] = line
+		line_number = line_number + 1
+	end
+	io.close(input)
+end
+
+function random_messages.display_message(message_number)
+	if random_messages.messages[message_number] then
+		minetest.chat_send_all(random_messages.messages[message_number])
+	end
+end
+
+function random_messages.show_message()
+	random_messages.display_message(math.random(#random_messages.messages))
+end
+
+--When server starts:
+random_messages.set_interval()
+random_messages.read_messages()
+
+local TIMER = 0
+minetest.register_globalstep(function(dtime)
+	TIMER = TIMER + dtime;
+	if TIMER > MESSAGE_INTERVAL then
+		random_messages.show_message()
+		TIMER = 0
+	end
+end)
+