Adding Class and functions for a shopping list object
Moved ShoppingList class to new file and added tests for ShoppingList.add_list()
Adding tests for ShoppingList.remove_from_list()
Add tests for ShoppingList.purchase_item(), changed return value when item is purchased
Adding a setup class
Adding tests for ShoppingList.show_list()
Changing spacing and imports.
Merge pull request #4 from raphaeladam-wf/class_shopping_list

Adding Class and functions for a shopping list object
fixing merge conflicts