Implemented option to include images attached to tweets.
`config.showImages` defaults to `false`, but if set to `true`, the tweet's image will be extracted (if present) and included within a `p.media` element after the `p.tweet` element - this currently extracts the largest image provided (if multiple sizes are attached).
exampleUsage.js has been updated to demo functionality, and twitterFetcher_min has been re-minifed to include latest changes.