add getCost() to calculate cost of trade goods.
add getCost() to calculate cost of trade goods.
Merge branch 'noora' of https://github.com/Rrego6/space_traders into noora
minor changes to controller
created Enum renamed tradegood
the enum trade good class
Merge branch 'noora'

Conflicts:
	SpaceTrader/src/controller/PlanetDrawScreenController.java