SkyEpub 7.2.2 for iOS Released

# Reflowable Layout

1. fixed the issue that TTS not working in the last page of each chapter.
2. fixed the issue that current page is jump back to the previous page while TTS is playing sometimes.
3. fixed the issue that highlight is not displayed properly in RTS and vertical writing mode.
4. fixed the issue that highlight for only one character is not displayed in RTS and vertical writing mode.