For all manually-created images PNG have been kept.
- rename all icon attrs to have a `ic_` prefix
- always use `_24dp` icons, because there is no real difference, since they are vector drawables
- always use the original name found on material.io for icon drawables, as to not create confusion and possibly duplicates. Icon names can still be different from real drawable names, though I have made some of them compliant to this or maybe more meaningul.
- remove duplicate `getIconByAttr()` in ThemeHelper (use `resolveResourceIdFromAttr()`
- use standard icons for `expand_more` and `expand_less` instead of triangles
- use `play_button_outline` instead of custom PNG as play button in VideoDetailFragment (questionable, as there is no shadow anymore)
- main, background, popup players now connected via one service, one view, one fragment, one activity and one gesture listener
- playback position is synchronized between players. Easy to switch from one to another
- expandable player at the bottom of the screen with cool animation and additional features like long click to open channel of a video, play/pause/close buttons and swipe down to dismiss
- in-player integrated buttons for opening in browser, playing with Kodi, sharing a video
- better background playback that can be activated in settings. Allows to automatically switch to audio-only mode when going to background and then switching to video-mode when returning to the app.
* restore permission request popup previously removed in #2486
* use legacy file picker in cases where saf file picker is not available
* fix missing file check logic in prepareSelectedDownload method (DownloadDialog.java)
- Migrate to fragments
- Fix#487
- Don't show "Open in popup mode" to channel links
- New backstack of videos
- Change the subscribers count to format using `NumberFormat`, for example some locales use `.` others `,`, this handles it automatically (and the old method had a bug for leading zero, e.g. 4.82.125 instead of 4.082.125)
- Add string 'subscribers' for channels with more than 1 subscriber (plural)
- Popup player chooses the default format and resolution based on the new preference (format)
- Fix taskaffinity of the router activities
- Show title before loading, as it is available from the items already loaded
