Displays the book information for the current post.
You can also use it to display the information from a different post by adding extra parameters with the title and author.
[book-info title="Book Title" author="Author Name"]
Displaying sub-book information.
If you have more than one book in a post, you need to display the book information for the "sub-books". To do that, you add an extra attribute for "number".
Where the number is the number of the sub-book in your list.