Fix initialize method for Book class
Create status local variable and reader in Book class
Add check_out method to class Book
Modify check_out so books cannot be checked out twice
Add check_in method to class Book
Fix class Borrower initialize method
Modify book method. Add local var count. clas Library
Add register_new_book method, class Library
Fix check_out_book method
Modify check_out_book method in class Library
Library knows who checked out book. Add borrowed_books hash to class Library
Fix check_out_book method so borrower cannot check out a book that is already checked out
Add check_in_book method in class Library
Modify check_in_book to remove returned book from @borrowed_book hash
Modify check_out_book method so borrowers cannot check out more than one book
Modify available_books to return only books not checked out
Modify test to accomidate code
Refactor getter methods