Inspired by http://www.cs.unc.edu/~stotts/723/refactor/chap1.html

- Problem: we want an output in HTML and the charging rule could change.

- That long statement routine in the Customer does far too much. Many of the things that it does should really be done by the other classes.
- Extracting the Amount Calculation (extract method)
- Changing variables name
- Moving the amount calculation from Customer to Rental 
- Removing "temp variable" with "query", clearer meaning.
- Extracting Frequent Rental Points
- Move method to Rental
- Removing "temp variable" with "query", clearer meaning.
- htmlStatement()
- Moving the Rental Calculations to Movie
- frequent renter points moved to Movie
- static constructors to hide constants
- inheritance & state pattern