The issue reported by concerto [1] is a regression since af312830.

[1] https://conference.gajim.org:5281/muc_log/gajim/2019-09-10#df591057-8693-4e76-bbc2-334d839c6adc

All avatars are available under ~/.cache/gajim/avatars

see: https://lazka.github.io/pgi-docs/Gdk-3.0/classes/Cursor.html#Gdk.Cursor.new_from_name

Fixes #9800

Caches now also the circle clipping

Iterating over the css data causes performance issues on older machines

Fixes #9820

The latter is a maintained fork that runs natively on python2/python3
(without using the fragile 2to3), fixes deprecations, and has a passing
testsuite.

- Show reason when group chat is gone
- Follow redirect if one exists

- Show reason when group chat is gone
- Follow redirect if one exists

Gajim doesn't use GSettings, so data migration is not needed.
https://blogs.gnome.org/mclasen/2019/07/12/settings-in-a-sandbox-world/

This can be easier done by just removing the autojoin flag

The available options regarding closing tabs should be enough