License of source code ---------------------- GNU Lesser General Public License, version 2.1 Copyright (C) 2011-2017 Kahrl Copyright (C) 2011-2017 celeron55, Perttu Ahola Copyright (C) 2012-2017 Various Minetest Game developers and contributors This program is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.html