THIS USERSCRIPT IS SADLY DEPRECATED. Most of this UserScript functionality has been implemented by GitHub. The reply-feature that GitHub didn't implement, has been moved to it's own UserScript: Github Reply Comments.
Add features to enhance comments & wiki & contact page on Github and comments on Github Gist.
You can reply to issues, pull requests and inline comments by pressing the reply button on every comment.
Every comment field also got a toolbar, consisting of the following buttons: