License

[KOYK]

We should add a section encouraging modders to specify their asset license.

[pchote]

The readme already has a paragraph saying that the code must be GPL3 but that assets can be licensed differently. It makes sense to expand this to say that we encourage modders to explicitly state the asset license in their mod project and recommend a couple for different situations (e.g. CC BY-NC-SA if they are fine with others reusing their assets in other mods, or CC BY-NC-ND if not?)