0.21.7.1144 RC

- When you terminate Telegram X session from another device, all downloaded media will be erased as well. When Google Play Services are installed, Telegram X and TDLib will do its best to remove all data without need in opening the app once the device goes online.

This might be helpful in case your device is lost or stolen. You never know when this might happen, so be sure to keep Telegram X up-to-date.

Note this does not yet apply to media files which have been copied through "Save to Gallery/Downloads/Music" button;

- Improved push subscription. All beta users will be resubscribed to notifications after updating to this version as well.
- Fixed several log-in/log-out bugs
- Fixed polls can't be forwarded without re-entering the chat
- Updated TDLib: minor bugfixes

Next one will be stable, as I finish working on a change log (+ couple minor things).