Migrate types to DefinitelyTyped

[cyberixae]

I wrote some types signatures for the redux-duck library. It creates FSA actions so I used the types from flux-standard-action for those. Then I opened a pull request against DefinitelyTyped that is the de facto place for storing javascript library type signatures. However, it turns out that linking to types that are not part of the DefinitelyTyped repository is problematic. It seems they only do it for substantial libraries written in TypeScript. I'm now wondering if you are perhaps interested in migrating your index.d.ts to DefinitelyTyped to make it's reuse easier.