Opening a url you've already opened in another loaded tab will move the older tab at the position of the newer tab, and close the new tab. There also is an option, in the add-on popup menu, a way to add text-matching rules. If a new tab's url matches that text and another opened tab also matches it, they will be considered the same url. This is particularly useful for webapps (discord.com, ...) This release is more of a test than anything, but it does the job fairly well. The code will be open-sourced when I'll take the time to. Comments are welcome.
