0.21.0.996 RC

- Android Pie: inline photos & stickers in notifications: Settings > Notifications > Image Preview. Auto-download settings apply.
- Android Pie: markdown now works properly
- Android Pie: name & picture in notifications displays properly
- "Done" button in notifications
- Updated TDLib
- Fixed: user name overlays "admin" sign
- Fixed: Invite Friends doesn't work without network connection
- Fixed: Tabs disappear on main screen after changing & reverting current language
- Other improvements & bugfixes