Dynamic API polling system

[AdamSalma]

Create an API watcher that handles updating parts of the state dynamically, enabling a central store for external content updates.

The initial idea is something similar to the following:

// Inside redux state tree
watch: [
    {
        url: '/api/4chan/g',       // API url to monitor
        interval: 10,              // seconds to pause for
        type: BOARD_UPDATED,       // Action to use when a url returns a 200 HTTP response code
        lastRequestAt: 140374197,  // unix timestamp
        expireOnError: true        // Remove this object when a bad status code occurs, excluding 304s
    },
    { /* And so on... */}
]

The type key is used as the dynamic action type when an item is updated.

This allows for a single service to:

• Loop over the watch items,
• Select any that are due to be checked,
• Check them by requesting the API url
• If a 200 http code is returned, use the type to broadcast the response to a particular node of the redux state.

This can be efficiently implemented inside a React container that enables/disables itself when there are/aren't any items to watch.

IDEA: Add an optional normalizr schema in each object to convert the response data before dispatching it.