Suggestion: Support to generate keys and extract sets that are personally downloaded.

[TomTurbine]

Thinking of this mainly in regards to being able to extract the No-Intro CDN sets for those who have it since it doesn't include the key files normally.

Edit: Now that I think about it, just having a separate application just to handle processing of the No-Intro sets would likely be pretty popular as that will likely be an increasingly used method after time, especially with how people like to have audited versions of their files.