Planet.java: created getSolarySystem() method
Ship.java:  Added the following:

Ship:
Attributes:
fuel (ship’s current fuel)
maxfuel (ship’s max fuel)
xLocation (current x-location of the ship)
yLocation (current y-location of the ship)

Methods:
getFuel()
addFuel() (add fuel to the ship)
getMaxFuel()
canTravelTo(solarsystem) (returns boolean)
canTravelTo(planet) (same as above)
travel(solarsystem) (travels, sets appropriate values)