License the project under a free software license
This project currently is not licensed, and by default, copyright law doesn't allow anyone to use, study, modify and distribute it without the explicit permission of the author.
I imagine this is simply an oversight, so this MR retroactively licenses the project under a free software license, which allows everyone to use, study, modify and distribute the code.
I've chosen GNU GPL v3 as the license, as it's widely used, and also requires any published modifications to include source code under the same license. For a more detailed summary, see https://choosealicense.com/licenses/gpl-3.0/.
Changing licensing terms requires the consent of all contributors, so I'm asking all of you if you agree with this change:
Edited by Grzesiek11