Many changes. Customer no longer inherits person. Methods to write XML
and read both customers and persons data files are written and working. 
Address class created and utilized.

Many of these changes will need to be reflected in the design document.

Still need to: 
Write code to handle products.
Make code self executable.
Clean up and tweak to get desired results.
Merge pull request #1 from ccunning2/Second

Many changes. Customer no longer inherits person. Methods to write XML