Add support to compose only functions in utils/compose

[evilj0e]

In our project we found some case that can brake your application.
It can be broken when you've tried to pass not a function in enhance array to compose function.

const toEnhance = [
    router.enhancer,
    applyMiddleware(...middleware),
    window && window.__REDUX_DEVTOOLS_EXTENSION__ && window.__REDUX_DEVTOOLS_EXTENSION__() // false in this case will cause a bug
];
const enhancer = compose(...toEnhance);

Of course I can filter array before passing it to enhancer, but I think it will be useful to manage it in compose function.

[chevsky]

You still can avoid this "bug" in one line if you want.

((window || {}).__REDUX_DEVTOOLS_EXTENSION__ || (() => store => store))()

[markerikson]

I could see some value in this. I know that @jimbolla added a somewhat similar check to React-Redux's connect in v5. Maybe gate the check behind a NODE_ENV check so it only happens in dev?

/cc @timdorr

[timdorr]

This is basically what I was thinking here. LGTM. Thanks!