Document the approach - recreating layout instead of embedding 

Same issue as https://github.com/abraham/twitter-status/issues/75 - looks like this component does a lot of work to recreate Twitter's layout. [Other components](https://github.com/capaj/react-tweet-embed) use the embedding API. How should a developer choose? The superiority of this component's approach might be lost on those who think "Oh, I can just use the embedding API/component".