Fix Twitter per Jonathan Suh

Fix dumb things about the Twitter and TweetDeck on the web.
- Always show “replying to” in replies and threads.
- Enable old school @-mention replies.
- Replace t.co links with the original links (wherever possible).
- Hide “in-case-you-missed” suggested tweets.

Details:
- Should replace most (but not all) t.co links—it only replaces ones where the data of the original URL is available in the code.
- Runs in the background and only executes in tabs open to twitter.com or tweetdeck.com.
- Runs every 3 seconds (polling interval customizable in options). Only shows hidden “replying to” that haven’t already been restored and only replaces new t.co links that haven’t already been changed (i.e. when you first load twitter.com, navigate to a new page, open a modal, load more tweets, etc.)
- Permission is listed as being able to “Read and change your data on tweetdeck.twitter.com and twitter.com” but none of your data is being read, stored, sent or otherwise by me or anyone else.
- If you’re curious or skeptical, I open-sourced this extension so you can see what’s happening under the hood at https://github.com/jonsuh/fix-twitter.