License for the cheatsheets

[ghisvail]

Hi Samuel, many thanks for the beautiful cheatsheets.

Could you clarify under which license(s) the cheatsheets can be redistributed?

I am thinking about aggregating a few cheatsheets for my research lab, and need to track individual licenses for them.

Best regards,

[sswatson]

I should add it to the repo, but you can put these down as CC0.