Fix incorrect statement of what the GPLv3 requires

[eternaleye]

In the README, there is the following line:

This source code is distributed under the GPL v 3.0 license. In short, this means that ALL modifications and/or derivative works that use all or any portion of source code in the repository must be made public.

This is thoroughly incorrect:

Does the GPL require that source code of modified versions be posted to the public?

The GPL does not require you to release your modified version, or any part of it. You are free to make modifications and use them privately, without ever releasing them. This applies to organizations (including companies), too; an organization can make a modified version and use it internally without ever releasing it outside the organization.

But if you release the modified version to the public in some way, the GPL requires you to make the modified source code available to the program's users, under the GPL.

Thus, the GPL gives permission to release the modified program in certain ways, and not in other ways; but the decision of whether to release it is up to you.

In short:

1. If no modified version is ever distributed, nothing ever needs to be released to anyone at all.
2. If a modified version is distributed, then the modified source code must be released to the recipients of the modified version.