Create PizzaShop.cs

http://stackoverflow.com/questions/2707401/please-help-me-understand-the-decorator-pattern-with-a-real-world-example
http://stackoverflow.com/questions/1673841/examples-of-gof-design-patterns/2707195#2707195
http://www.programcreek.com/2012/05/java-design-pattern-decorator-decorate-your-girlfriend/
http://en.wikipedia.org/wiki/Decorator_pattern
http://www.oodesign.com/decorator-pattern.html
http://www.tutorialspoint.com/design_pattern/decorator_pattern.htm