Migrate to Torbutton 1.6

Torbutton 1.5.x will probably be EOL as soon as TBB 3.0 is stable (which is blocked on just a couple bugs), so we have to migrate ASAP. The branding additions in 1.6.x may conflict with ours.

Mike Perry writes:

The main things I’d be worried
about if I were you is dealing with Tor Launcher and 1.6.x. Leaving Tor
Launcher out but Torbutton 1.6.x in might cause some problems. You can
also try including Tor Launcher in with extensions.torlauncher.start_tor
set to false, but it still may complain if you don’t set the
TOR_CONTROL_PORT and TOR_CONTROL_PASSWD env vars anyway.

… so this is related to #5343 (closed).

Feature Branch: feature/ff24

Related issues

• Related to #5343 (closed)
• Related to #6370 (closed)

Original created by @intrigeri on 6371 (Redmine)