get_path_to_generic_or_avatar() is not available anymore in
gtkgui_helpers, its enough to load avatars from cache

Fixes #241, #251

[clients_icons] Fix Dino icon and add Pix-Art Messenger

See merge request gajim/gajim-plugins!58

Fixes #250

[UrlImagePreview] Add PNG and GIF thumbnails to url_image_preview.py

Closes #234

See merge request gajim/gajim-plugins!53

[client_icons] Adds Dino client icon

Closes #212

See merge request gajim/gajim-plugins!52

[OMEMO] Make some strings translatable

See merge request gajim/gajim-plugins!51

[ubuntu_dock] Add plugin

See merge request gajim/gajim-plugins!49

We would receive a KeyError for jids we dont have in the roster,
now we skip them and print a warning.

Fixes #173

This is due a update to ejabbered where Nodes
can now hold 10 items per default

This is only a BytesIO Object in memory, its becomes garbage collected
after the method ends anyway

Fixes #232

Support 12bit IVs on encrypted httpupload files

[plugin_installer] do not update plugin if it's not compatible with current Gajim version. Fixes #225

[omemo] Reword the manifest.ini description

Closes #224

See merge request !40