Setting-related:
minetest.setting_set(name, value)
minetest.setting_get(name) -> string or nil
+minetest.setting_setbool(name, value)
minetest.setting_getbool(name) -> boolean value or nil
minetest.setting_get_pos(name) -> position or nil
minetest.setting_save() -> nil, save all settings to config file