core: add position manager system

it doesn't save them to disk, but that would not be too difficult to add

worldeditadditions_core/core/pos.lua

@@ -0,0 +1,57 @@
+local wea_c = worldeditadditions_core
+
+local positions_count_limit = 999
+local positions = {}
+
+local function ensure_player(player_name)
+	if not positions[player_name] then
+		positions[player_name] = {}
+	end
+end
+
+--- Gets the position with the given index for the given player.
+-- @param	player_name		string	The name of the player to fetch the position for.
+-- @param	
+local function get_pos(player_name, i)
+	ensure_player(player_name)
+	return positions[player_name][i]
+end
+
+local function get_pos1(player_name) return get_pos(player_name, 1) end
+local function get_pos2(player_name) return get_pos(player_name, 2) end
+
+local function get_pos_all(player_name)
+	ensure_player(player_name)
+	return positions[player_name]
+end
+local function pos_count(player_name)
+	ensure_player(player_name)
+	return #pos_count[player_name]
+end
+
+local function set_pos(player_name, i, pos)
+	if i > positions_count_limit then return false end
+	ensure_player(player_name)
+	positions[player_name][i] = pos
+	return true
+end
+local function set_pos_all(player_name, i, pos_list)
+	if #pos_list > positions_count_limit then return false end
+	positions[player_name] = pos_list
+end
+local function clear(player_name)
+	if positions[player_name] then
+		positions[player_name] = nil
+	end
+end
+
+return {
+	get = get_pos,
+	get1 = get_pos1,
+	get2 = get_pos2,
+	get_all = get_pos_all,
+	set = set_pos,
+	set_all = set_pos_all,
+	count = pos_count,
+	clear = clear
+}

worldeditadditions_core/init.lua

@@ -26,6 +26,7 @@ local wea_c = worldeditadditions_core
 wea_c.register_command = dofile(modpath.."/core/register_command.lua")
 wea_c.fetch_command_def = dofile(modpath.."/core/fetch_command_def.lua")
 wea_c.register_alias = dofile(modpath.."/core/register_alias.lua")
+wea_c.pos = dofile(modpath.."/core/pos.lua")
 
 
 -- Initialise WorldEdit stuff if the WorldEdit mod is not present