Keep Twitter scroll position

When you're browsing the replies, and replies-to-replies, of a popular tweet, you may be surprised to see that hitting the back button from a 'replies-to-replies' thread puts you back at the start of the original reply thread, instead of at the position you last were. You now have to scroll down (sometimes a long way down) to continue your reading of the original tweet's replies. This extension fixes the user experience by auto-scrolling to your last position in the reply thread, and highlighting the tweet you last read. This extension is open-source. The source code is here: https://github.com/ackinc/keep-twitter-scroll-position