Added Keys to JSON goods. Added Buybar with Ship goods.
Merge branch 'master' into sam/dev

Conflicts:
	src/main/java/edu/gatech/gem5/game/controllers/MarketController.java
Revised the MVC framework by introducing a Controller superclass for all controllers.
Merge branch 'master' of https://github.com/gem-5/last-adventures into creston/dev

Conflicts:
	src/main/java/edu/gatech/gem5/game/Planet.java
	src/main/java/edu/gatech/gem5/game/controllers/DisplayUniverseController.java
	src/main/java/edu/gatech/gem5/game/controllers/MarketController.java
Got Selling Goods Panel to appear.
Merge branch 'sam/dev'

Conflicts:
	src/main/java/edu/gatech/gem5/game/Planet.java
	src/main/java/edu/gatech/gem5/game/controllers/MarketController.java
Added back button.
Improved the code at @MarketController.java
Implemented sell, not validate sell
Fixed Nullpointer bugs in MarketController.
merge fix
Merge branch 'master' of https://github.com/gem-5/last-adventures

Conflicts:
	src/main/java/edu/gatech/gem5/game/controllers/MarketController.java
	src/main/resources/market.fxml
Fixed some errors. Added some changes to the DisplayUniverse controller.
Merge branch 'master' of https://github.com/gem-5/last-adventures
Properly merged.
Merged the change of Ship.getCargoCount from Good to GoodType
fixed double import of util.Map
Buying and Selling goods works as needed for demo. Currently, planet's stock will be redetermined each time you buy or sell a product.
Prints error message in the GUI instead of in console @market
Merge master into alex/dev

Conflicts:
	src/main/java/edu/gatech/gem5/game/controllers/DisplayUniverseController.java
	src/main/java/edu/gatech/gem5/game/controllers/MarketController.java
	src/main/resources/market.fxml
Fixing errors created by previous merge