Do not allow swiping between books if option is set

[davidmoore1]

Currently the < > buttons will always transition to the next or previous book if you are at the end or beginning of a book. If the option to allow swipe between books, set in Book Navigation section of SAB, is not checked, then the < or > button should not appear and you should not be able to swipe between books. The option is controlled by "book-swipe-between-books" in main-features. If it is false, you should not be able to swipe between books.