replace BaseComponent with a functional connection API

[Ma27]

Description of the issue

the BaseComponent is a simple hack in the spec of this implementation which shouldn't exist as public API classes should be avoided (https://medium.com/@dan_abramov/how-to-use-classes-and-sleep-at-night-9af8de78ccb4#.jm9evg8ba) and the BaseComponent is something that should be removed.
Instead a lightweight connection library could be created:

// add.
componentDidMount() {
  connector(storeObj).useWith(this.handler);
}

// remove.
componentWillUnmount() {
  connector(storeObj).unsubscribe(this.handler);
}

What's with the BaseStore

the big issue of the components is the hacky OO approach: we declare properties in the constructor of the component, use super calls in our lifecycle hooks to make the subscription work build a even bigger component structure which is harder to understand.

The BaseStore utilizes the approach of creating a simple and dumb data object which flushes changes in its state to the view. Stores should be instantiated as they're just simple objects and the instance should be passed to module.exports and not the class. Therefore the BaseStore is not a big design issue, but the BaseComponent is.

[Ma27]

@benbieler what do you think??

[Ma27]

another improvement would be that we can resolve the peer dependency to react