Audio player improvements
Audio player improvements

- Audio can be heard even if the lock/vibrate toggle is on
- Added `isPlaying` method
- Fixed the sync timer so that it works even when a webview is being scrolled

danfsd/FolioReaderKit,Julyyq/FolioReaderKit,Julyyq/FolioReaderKit,FolioReader/FolioReaderKit,taku33/FolioReaderPlus,ShenghaiWang/FolioReaderKit,kjantzer/FolioReaderKit,ShenghaiWang/FolioReaderKit,taku33/FolioReaderPlus,danfsd/FolioReaderKit,FolioReader/FolioReaderKit,smartmobilefactory/FolioReaderKit,smartmobilefactory/FolioReaderKit,smartmobilefactory/FolioReaderKit,FolioReader/FolioReaderKit,kjantzer/FolioReaderKit,taku33/FolioReaderPlus,Julyyq/FolioReaderKit,ShenghaiWang/FolioReaderKit,danfsd/FolioReaderKit,kjantzer/FolioReaderKit