Tab Ceiling por brp

This is a very simple add-on I made to get my tabs under control. It does four things:

1. Allows you to set a tab ceiling, above which new tabs will be blocked from opening. (Android: just block new tabs from opening, since Android add-ons have no way of counting open tabs).
2. Allows you to change links so that they won't open in new tabs. This can be turned on in settings.
3. Distinguishes between old and new tabs, to prevent from closing tabs as they reopening after inactivation (on Android) or after a session restore (on Desktop).
4. Provides a settings pop-up to allow configuration of each of the above behaviors.

Usage:
1. Install the add-on
2. Open the add-on widget from the toolbar
3. Configure number of tabs to limit to, and whether links should be overridden.
I personally prefer the config that links are not overridden, because I'm afraid of losing state when the override unexpectedly opens a link in the current tab.
4. Enjoy!

On FF Android, addons are unable to access the current number of open tabs, and so we have a toggle to plck new user-opened tabs. Newly re-activated tabs are not counted or blocked. If they are, please file a bug.

This add-on is still only lightly tested on Android. It seems to behave correctly on FF desktop. That said, if you test it and find an issue, please file the issue on github.