Major cleanup.

- Use `irc.foo` notation instead of `irc:foo`. It still
  supports the `irc:foo` usage, but will helpfully issue
  a warning with the location of the offending code.
- Remove unused arguments from functions.

botcmds.lua

@@ -15,7 +15,7 @@ local function nickequals(nick1, nick2)
 	return irclower(nick1) == irclower(nick2)
 end
 
-function irc:check_botcmd(msg)
+function irc.check_botcmd(msg)
 	local prefix = irc.config.command_prefix
 	local nick = irc.conn.nick
 	local text = msg.args[2]
@@ -25,18 +25,18 @@ function irc:check_botcmd(msg)
 	-- First check for a nick prefix
 	if nickequals(nickpart, nick)
 			and (suffix == ": " or suffix == ", ") then
-		self:bot_command(msg, text:sub(#nick + 3))
+		irc.bot_command(msg, text:sub(#nick + 3))
 		return true
 	-- Then check for the configured prefix
 	elseif prefix and text:sub(1, #prefix):lower() == prefix:lower() then
-		self:bot_command(msg, text:sub(#prefix + 1))
+		irc.bot_command(msg, text:sub(#prefix + 1))
 		return true
 	end
 	return false
 end
 
 
-function irc:bot_command(msg, text)
+function irc.bot_command(msg, text)
 	-- Remove leading whitespace
 	text = text:match("^%s*(.*)")
 	if text:sub(1, 1) == "@" then
@@ -44,15 +44,15 @@ function irc:bot_command(msg, text)
 		if not player_to then
 			return
 		elseif not minetest.get_player_by_name(player_to) then
-			irc:reply("User '"..player_to.."' is not in the game.")
+			irc.reply("User '"..player_to.."' is not in the game.")
 			return
 		elseif not irc.joined_players[player_to] then
-			irc:reply("User '"..player_to.."' is not using IRC.")
+			irc.reply("User '"..player_to.."' is not using IRC.")
 			return
 		end
 		minetest.chat_send_player(player_to,
 				"PM from "..msg.user.nick.."@IRC: "..message, false)
-		irc:reply("Message sent!")
+		irc.reply("Message sent!")
 		return
 	end
 	local pos = text:find(" ", 1, true)
@@ -65,36 +65,36 @@ function irc:bot_command(msg, text)
 		args = ""
 	end
 
-	if not self.bot_commands[cmd] then
-		self:reply("Unknown command '"..cmd.."'. Try 'help'."
+	if not irc.bot_commands[cmd] then
+		irc.reply("Unknown command '"..cmd.."'. Try 'help'."
 			.." Or use @playername <message> to send a private message")
 		return
 	end
 
-	local _, message = self.bot_commands[cmd].func(msg.user, args)
+	local _, message = irc.bot_commands[cmd].func(msg.user, args)
 	if message then
-		self:reply(message)
+		irc.reply(message)
 	end
 end
 
 
-function irc:register_bot_command(name, def)
+function irc.register_bot_command(name, def)
 	if (not def.func) or (type(def.func) ~= "function") then
 		error("Erroneous bot command definition. def.func missing.", 2)
 	elseif name:sub(1, 1) == "@" then
 		error("Erroneous bot command name. Command name begins with '@'.", 2)
 	end
-	self.bot_commands[name] = def
+	irc.bot_commands[name] = def
 end
 
 
-irc:register_bot_command("help", {
+irc.register_bot_command("help", {
 	params = "<command>",
 	description = "Get help about a command",
-	func = function(user, args)
+	func = function(_, args)
 		if args == "" then
 			local cmdlist = { }
-			for name, cmd in pairs(irc.bot_commands) do
+			for name in pairs(irc.bot_commands) do
 				cmdlist[#cmdlist+1] = name
 			end
 			return true, "Available commands: "..table.concat(cmdlist, ", ")
@@ -116,20 +116,20 @@ irc:register_bot_command("help", {
 })
 
 
-irc:register_bot_command("list", {
+irc.register_bot_command("list", {
 	params = "",
 	description = "List available commands.",
-	func = function(user, args)
+	func = function()
 		return false, "The `list` command has been merged into `help`."
 				.." Use `help` with no arguments to get a list."
 	end
 })
 
 
-irc:register_bot_command("whereis", {
+irc.register_bot_command("whereis", {
 	params = "<player>",
 	description = "Tell the location of <player>",
-	func = function(user, args)
+	func = function(_, args)
 		if args == "" then
 			return false, "Player name required."
 		end
@@ -145,9 +145,9 @@ irc:register_bot_command("whereis", {
 
 
 local starttime = os.time()
-irc:register_bot_command("uptime", {
+irc.register_bot_command("uptime", {
 	description = "Tell how much time the server has been up",
-	func = function(user, args)
+	func = function()
 		local cur_time = os.time()
 		local diff = os.difftime(cur_time, starttime)
 		local fmt = "Server has been running for %d:%02d:%02d"
@@ -160,9 +160,9 @@ irc:register_bot_command("uptime", {
 })
 
 
-irc:register_bot_command("players", {
+irc.register_bot_command("players", {
 	description = "List the players on the server",
-	func = function(user, args)
+	func = function()
 		local players = minetest.get_connected_players()
 		local names = {}
 		for _, player in pairs(players) do