Support tweets longer than 140 characters

[YtvwlD]

Twitter calls these "extended tweets" and they're handled differently: https://developer.twitter.com/en/docs/tweets/data-dictionary/overview/intro-to-tweet-json#extendedtweet

Currently, all tweets are capped at ~140 characters and get a "…" appended.
Or we might want to keep it this way, because fitting an even longer text in the box will be difficult.

[YtvwlD]

Closing for #28