The Adwaita theme's icon set (#45).

adwaita-icon-theme 51.0, the GNOME Project (AUTHORS, beside this file).
https://gitlab.gnome.org/GNOME/adwaita-icon-theme, commit 70ecd52fbe844304ed4f845a04a1757fa6284884.
Licence: GNU LGPL v3 or CC BY-SA 3.0 US, the recipient's choice (COPYING); Zephyrus takes the LGPL v3
(LICENSE, beside this file; the GNU GPL v3 it builds on is Zephyrus's own LICENSE, at the top of the
repository).

Each file is one of the theme's icons, unchanged, renamed to the need Zephyrus uses it for
(crates/app/src/themeicons.rs lists them):
- 16/<need>.png: Adwaita/16x16/<context>/<icon>.png, a colour picture.
- 24/<need>.svg: Adwaita/scalable/<context>/<icon>.svg, a colour drawing (drawn at 24 pixels
  and up).
- 16/ and 24/<need>-symbolic.svg: Adwaita/symbolic/<context>/<icon>-symbolic.svg, a one-colour
  icon; Zephyrus draws its greys in the theme's text colour as it reads it, as GNOME does.

Which icon each need is (and the stand-ins, where Adwaita has no icon of that meaning):
  tb-add-url: list-add-symbolic
  tb-add-torrent: insert-link-symbolic (stand-in)
  tb-resume: media-playback-start-symbolic
  tb-stop: media-playback-stop-symbolic
  tb-stop-all: process-stop-symbolic (stand-in)
  tb-delete: edit-delete-symbolic
  tb-delete-completed: edit-clear-all-symbolic (stand-in)
  tb-options: preferences-system-symbolic
  tb-scheduler: alarm-symbolic
  tb-start-queue: media-seek-forward-symbolic (stand-in)
  tb-stop-queue: media-playback-stop-symbolic (stand-in)
  cat-all: folder
  cat-compressed: package-x-generic
  cat-documents: x-office-document
  cat-music: audio-x-generic
  cat-programs: application-x-executable
  cat-video: video-x-generic
  cat-torrents: folder-remote (stand-in)
  cat-unfinished: folder-download
  cat-finished: folder (stand-in)
  cat-queues: view-list-symbolic (stand-in)
  cat-folder: folder
  cat-folder-open: folder-open-symbolic
  st-complete: object-select-symbolic
  st-error: dialog-error-symbolic
  st-paused: media-playback-pause-symbolic
  st-downloading: go-down-symbolic
  st-queued: appointment-soon-symbolic
  st-seeding: go-up-symbolic
  ft-generic: application-x-generic
  ft-archive: package-x-generic
  ft-audio: audio-x-generic
  ft-video: video-x-generic
  ft-image: image-x-generic
  ft-document: x-office-document
  ft-spreadsheet: x-office-spreadsheet
  ft-presentation: x-office-presentation
  ft-executable: application-x-executable
  ft-code: text-x-script
  ft-text: text-x-generic
  ft-disk-image: media-optical, media-optical-symbolic (stand-in)
  ft-font: font-x-generic
  ui-minimize: window-minimize-symbolic
  ui-maximize: window-maximize-symbolic
  ui-restore: window-restore-symbolic
  ui-close: window-close-symbolic
  misc-emblem-ok: object-select-symbolic
  misc-up: go-up-symbolic
  misc-down: go-down-symbolic
  misc-remove: list-remove-symbolic

Zephyrus's own, drawn for Zephyrus in Adwaita's style and colours (GPL-3.0-or-later, as Zephyrus), where
Adwaita has no icon of that meaning, at 16, 24, 32 and 48 pixels: ft-pdf (a page with a "PDF"
label) and ft-torrent (a page with a magnet), colour pictures (<need>.png), and ui-to-tray (a
window going down to the notification area), a one-colour picture (ui-to-tray-symbolic.png)
drawn in the theme's text colour. Any can be swapped for another file of the same name.
