* Proof-of-concept for showing card tags (#1626)
* Resolved most PR comments:
- Added a snackbar notification when clicking tag button
- Replaced magnifying glass icon with new tag icon
- Button now contains a span w/icon, to use text color
- Removed unnecessary attributes from button
- Backend now returns full noteInfos object
- Frontend now handles filtering tags
* Add options to show/hide tag button & filter tags
* Do not show tags button if, after filtering, we have zero tags.
* Change tags option to enums, optimize tags intersection check & fix code style.
* Update options-util.js to include new tag options.
* Fix wording on new tag setting.
* Add CSS to remove hidden buttons from the display layout.
* getAnkiNoteInfo extra parameter for additional info.
* Add new tag option to tests.
* Remove unnecessary changes related to anki tags option.
* Code style fixes.
* Update environment info to return the 'safari' browser
* Fix popup display on Safari
* Update environment assignment
* Add data-loading-stalled property when loading takes longer than expected
* Add notification when loading has stalled
* Allow getDictionaryInfo invocation on non-privileged contexts
* Update _validatePrivilegedMessageSender
* Don't listen to 'voiceschanged' event unless addEventListener is present
Also expose an event
* Add double-down-chevron.svg
* Add options
* Update dictionary importers
* Update settings
* Add support for collapsible definitions
* Improve case when there is a very small amount of overflow
* Fix incorrect enabled state of newly imported dictionaries
* Update PopupMenu event prevention
* Use vars for button padding
* Add button-inner-label style
* Add input-button button
* Update display of scope selection
* Add hidden argument text input field
* Remove unnecessary calls
* Display a strike through the enabled button when no scopes are selected
* Improve grouping for inflection and expression styles
* kanji-link => expression-kanji-link
* Remove unnecessary entry-header2 and entry-header3
* Move tag list into header for consistency with term definitions
* Move styles
* Add clear
* Replace :not(:disabled) styles
* Use var for style
* Update active styles
* Update disabled styles for <input> elements
* Update button disabled styles
* Add focus styles to checkbox
* Update style name
* Add card icon to audio menu items
* Update cache data format
* Create _getCacheItem
* Add _playAudioFromSource function
* Implement default card audio info
* Specify exact audio to download when an override is assigned
* Abstract using _getMenuItemSourceInfo
* Update downloadability check
* Update the main audio menu buttons to also assign the default source
