implemented calculate winner and needed int in in car to hold winpoints.

src/main/java/ch/zhaw/pm2/racetrack/Car.java

@@ -24,6 +24,10 @@ public class Car implements CarSpecification {
      * Current position of the car on the track grid using a {@link PositionVector}
      */
     private PositionVector position;
+    /**
+     * Points that car is holding for determining winner.
+     */
+    private int winPoints;
 
     /**
      * Current velocity of the car using a {@link PositionVector}
@@ -59,6 +63,18 @@ public class Car implements CarSpecification {
         return id;
     }
 
+    public void increaseWinPoints() {
+        winPoints ++;
+    }
+
+    public void deductWinPoints() {
+        winPoints --;
+    }
+
+    public int getWinPoints() {
+        return winPoints;
+    }
+
     /**
      * Returns the current velocity of the car as a PositionVector.
      *