Consider export option to reassemble truncated retweets

[kerchner]

Retweets of a certain length can truncate the original tweet in the text field. However, the original tweet is nested in the json. It might be a useful option to either add a column with the "original" text, and/or to merge both texts to fill in the truncated portion.

[lwrubel]

This was requested by a GW researcher who wanted to search on words in an exported spreadsheet, or otherwise read full retweets there.