Add license

[IBPX]

Without a license, it isn't legal (at least where I live) for anyone to use this library in their game, because you haven't given them permission (even though the code is right here). I would recommend adding either the MIT license or the zlib license.

• The MIT license requires that you give the library credit.
• The zlib license requires that you give credit in your source code, but binaries do not have to.

To add one of these licenses, you can put one of the following texts in a file called LICENSE.txt (or LICENSE.md).

zlib:

zlib License

(C) 2017 Zalo

This software is provided 'as-is', without any express or implied
warranty.  In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not
   claim that you wrote the original software. If you use this software
   in a product, an acknowledgment in the product documentation would be
   appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.

MIT:

MIT License

Copyright (c) 2017 Zalo

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

[Zal0]

MIT license has been added to the project

[tobiasvl]

This is great!

However, since you include GBT Player (which is licensed under BSD-2) in ZGB, I think that picking the BSD-2 license here would perhaps have made more sense. See for example this discussion: https://softwareengineering.stackexchange.com/questions/121998/mit-vs-bsd-vs-dual-license

However, it might be unproblematic to use MIT for ZGB and still include GBT in it. See this discussion: https://softwareengineering.stackexchange.com/questions/278126/is-it-legal-to-include-bsd-licensed-code-within-an-mit-licensed-project

In any case, you would need to include the entirety of GBT's license in the relevant files. Right now you have a comment in a GBT file, saying it's copyright AntonioND, but you do not include the rest of the license text there, as it requires.

(I'm assuming here that you haven't received a different license from AntonioND to use GBT Player in ZGB. You could probably just ask him if it's OK to do it the way you have done it now. If he says it's OK, you have received a license to use it.)

[AntonioND]

Oh, that's me. I don't have any problem with adding the license to my files so that you can distribute them with your ZGB. Just give me a couple of days.

[AntonioND]

I've cleaned the code quite a bit (specially mod2gbt): https://github.com/AntonioND/gbt-player/tree/v3.0.6

Please tell me if everything works as expected.