Custom `dispatch` parameter

[zalmoxisus]

As discussed in #4, it allows to separate the monitor app from watching actions and effects.

So, on the client side we use:

const monitor = createSagaMonitor({ dispatch: (action) => { window.postMessage(action, '*') } })
const sagaMiddleware = createSagaMiddleware({sagaMonitor: monitor})
const store = createStore(
  reducer,
  applyMiddleware(sagaMiddleware)
)
sagaMiddleware.run(rootSaga)

Then on the other side we get actions right in the monitor's store:

const sagaStore = createStore(sagaReducer)
function handleMessages(event) {
  sagaStore.dispatch(event.data)
}
window.addEventListener('message', handleMessages, false)

ReactDOM.render(
  <SagaMonitor monitor={{store: sagaStore}}  />,
  document.getElementById('root')
);

[yelouafi]

thanks!