Taylor edits

Hi Mike,

I compared the code to the test code, and removed methods and parameters in the following manner:

I only removed the body of the methods for the Library class, leaving in the parameters. The Library class has the most information.

I removed the body of the methods and the parameters for the Borrower class. This class has the second most information.

I removed all the methods except for the Initialize method for the Book class. This class has the least amount of information.

I figured that students should be able to piece this together by using the test code as a roadmap. Students who are able to successfully complete that should have enough knowledge to begin tackling extensions. 

What do you think?