Reflowable Layout

1. Fixed the bug when another ViewController is presented on the top of BookViewController, BookViewController disappears or not responsive sometimes.
2. Fixed the bug that Internal Server is not responding.
3. Fixed the bug that didDetectTap is not called after longPressing gesture.

Fixed Layout

1. Fixed the issue Initial Zoom Scale is too large at start time.
2. Fixed the bug that App crashed due to heap memory pressure when too large pages are loaded.