Please make licensing more explicit

Hello, I'm a Debian Maintainer which works on the pkg-security team and i'm very interested in packaging prochunter. The package would be picked by kali linux, ubuntu, and all of debian's derivatives.

Although, i would feel more confident if the license were a little more explicit, it seems that the only declaration of license right now is on https://gitlab.com/nowayout/prochunter/blob/master/prochunter.c#L102.

It would be nice if you could add a LICENSE file on the repository containing the the full GPLv2 delcaration (or any other license, if you want to change it), and also add a short header on prochunter.c and prochunter.py stating the copyright, example: https://github.com/traviscross/mtr/blob/master/packet/command.c#L1-L17

Thanks