Dart Version of uuidkey

[HudsonAfonso]

Hey, I really love your project, is it cool if I make a Dart version of this project?
I know it's MIT licensed, but figured I'd ask first.

[jackspirou]

Hi @HudsonAfonso - of course, we will be adding more features based on feedback (you can see the main items in this PR) - but we'd love to link to your Dart version!

[HudsonAfonso]

amazing, I'll be back with news :D

[jackspirou]

@HudsonAfonso - I merged the additional feedback into the master branch if your interested in reviewing it. Still backwards compatible but we added an APIKey type.

[tanhv90]

@jackspirou I love your project too and just make a Nodejs implementation here: https://github.com/tanhv90/uuidkey/
Thanks for your effort!