Modified addBorrower() and addBook() to check if borrower/book already
exist in database using sinOrStNo/isbn.  

Modified addBook() to add new book or new copy of an existing book.  

Completed searchBook().

Modified table.sql so that it can be run from SQLPlus command line.
NOTE if you haven't already made the tables, you need to cut the "drop
table"s from the beginning of the file before you can run the file.
Ran and tested.  See TODO comments about parts of methods that don't
work/cause errors.