mention license more

[DreadKnight]

Had some misfortune recently with an artist that made a fanart and used it for commercial purposes as well while refusing to respect the license which implies crediting the project and original artist.

Various pages such as units and media should contain a div with more specific license info in order to make things more obvious.

[DreadKnight]

It's not very obvious who made the characters in the units page, so I should address that as well soon.