Remove Flow types for now

[gaearon]

I decided in favor of not shipping Flow types in 1.0.
This commit just strips types from the current Flow-friendly codebase (initially worked on in #254).

We will not use features unsupported by Flow (such as let or const) from now on so it's easy to gradually add Flow types later.

The reason I'm removing them is they're too naive and I don't want them to be perceived as the public API (at least not yet). I am ready to add Flow when cases like this are solved. Adding them now is confusing because, for #290 to work, different (more polymorphic) signatures are needed. For example, Store type should be parameterized by <MyState, MyAction> instead of any types in the current annotations.

[gaearon]

cc @acdlite

[yanivtal]

Aww I was looking forward to this. Btw let/const should be in soon facebook/flow#431

[gaearon]

Haha. Help make it happen with the correct signatures :-)
I got stuck to be honest, but I really want to get #290 to work!

[leoasis]

@gaearon do you have any branch you could publish with your progress there? If you have done any significant progress it would be nice to start from there

[gaearon]

@leoasis

I had one but it descended into pointlessness so it would be easier for you to start fresh.
Some advice:

• Concentrate on createStore, don't add annotations anywhere else, this will only confuse you.
• Make it return Store<State, Action> where State and Action types are user specified.
• You'll have a problem with the dispatch of initial action because it won't match the user's Action type. Good luck there. :-P Maybe it's easiest to change signature to createStore<State, Action>(reducer: Reducer<State, Action>, initialState: State, initialAction: Action) just to get it to type check for now, and then figure out something that makes sense..

[gaearon]

The goal is to get #290 working at least in the minimal way of type checking action/state type validity with createStore. Then figure out how to get the rest of the API working. Middleware and higher order stores might get super tricky (if not impossible) because applyMiddleware(...) changes dispatch type with each middleware. Don't go there until you figure out the basics..

[leoasis]

Cool, will give it a good go tomorrow, thanks for the advice