tvOS compatibility

• The library is compatible with tvOS.
• The control center integration has been improved:
  • The seek bar can be used to navigate in the media being played.
  • When using AirPlay, subtitles and audio tracks can be changed directly from the control center.
  • Playback controls through Siri have been improved.
• Playback automatically resumes after audio interruption (e.g. phone call or alarm).
• Data consumption has been reduced.
• Fixed issue restarting stopped playback after network is reachable again.
• Fixed issue incorrectly leading to livestreams being paused instead of stopped when using split view.
• Semantic versioning has been adopted.
• The project has been renamed as srgletterbox-apple.