improve types

[no-stack-dub-sack]

@AntJanus per #200 updates the types for connect to allow for a null first argument in the event that your component does not require a mapStateToThis function.

Also, makes various updates to the types, and adds type annotations (taken from redux) for an improved intellisense experience. Updates to the types themselves include:

• replacing Reducer, MiddlewareArg, and Middleware with more precise types taken from redux typings
• removing getReducer, which is no longer part of the redux API (so far as I can tell)
• indicate that connect returns Unsubscribe
• replace references to Object with the non-primitive object type, in mapDispatchToTarget - though these types could definitely be improved further and made more specific to avoid referencing this as all, however, I didn't have the time today to put together really well thought out types for this.

Let me know what you think or if you'd like to see any changes to this.

closes #200

[bensgroi]

Great - being able to use generics with INgRedux.getState() would be really useful.

[no-stack-dub-sack]

@AntJanus ☝️ just a reminder on this PR. Any chance you can review?

[no-stack-dub-sack]

👍