create test for Topping#initialize to set the name var correctly; implemented Topping#initialize
added failing test to see if a topping is vegetarian
Topping.initialize now takes vegetarian bool as 2nd arg.  Added attr_reader
Topping.initialize assumes non-vegetarian unless specified in a keyword arg. Added a test to see if a topping object that isn't passed vegetarian status is still false. Passed.
Fixed logic error: pepperoni is not-veg.  Added passing test to ensure olives are veg.
Added failing test: pizzas should record their own toppings
Pizza class takes toppings, Pizza.toppings returns toppings.  Refactored tests slightly for re-use.
add failing test for pizzas to default to cheese
Pizza#new defaults to a cheese topping if none passed.