0.21.7.1157 RC

Updated library for calls, bugfixes.

- Updated libtgvoip to 2.5: Improved calls voice quality, fixed crashes and freezes during call
- Updated libopus to 1.3.1 used by libtgvoip
- Fixed: broken music & voice playback (starting 0.21.7.1155 version).

+ internal work on some fun feature, which will appear in one of the next updates.