• properly release cache on destroy of PlaybackService
• added menu item "Clear from cache" in AudioPlayer screen to remove current episode from cache
• further improvements and bug fixes in PlaybackService. improved power efficiency since 8.14.3
• in case of player error, no longer showing the daunting player error dialog, only toast messages
• player play/pause status is tracked by a state variable
• recent feed list in the drawer is expanded to 8
• straightened behaviors of navigation with default pages and open drawer
• PlayerErrorEvent and PlayEvent are no longer used and are removed