working on getResourcePrice(ResourceType type) in the Planet.java
Created the Cargo.java class
incorporated getting the rank of technology levels so we can derive an int out of the technology levels.
created a validateCargoSpace method to ensure we have enough space on the cargo before things are added to cargo
Merge branch 'master' of https://github.com/astrosnails/SpaceTraders into feature/M5_Models
added a constructor to the Ship class which takes in a String name, int cost, and a maxSize for the cargo. Also initialized the Cargo object with that maxSize.
updated the constructor signature for the ship class to also include the max of the cargo size.
updated the access modifier for the Cargo cargo object
added the import statement for the ArrayList
changed the type of resource the cargo contains
added the add, remove, and contains methods for the Cargo.java for addition, removal, and querying of resources.
updated the validateCargoSpace()
added getSpace() method to figure out how much cargo space is available
i added money limit, buy method, and sell method