Spun off Locatable interface to make collision code more reusable

#story[1100]

racevisionGame/src/main/java/visualiser/model/VisualiserRaceState.java

@@ -1,7 +1,6 @@
 package visualiser.model;
 
 
-import javafx.application.Platform;
 import javafx.collections.FXCollections;
 import javafx.collections.ObservableList;
 import javafx.scene.paint.Color;
@@ -228,7 +227,7 @@ public class VisualiserRaceState extends RaceState {
 
             boat.setCurrentLeg(startingLeg);
             boat.setTimeAtLastMark(getRaceClock().getCurrentTime());
-            boat.setCurrentPosition(new GPSCoordinate(0, 0));
+            boat.setPosition(new GPSCoordinate(0, 0));
 
         }
 
@@ -253,10 +252,10 @@ public class VisualiserRaceState extends RaceState {
 
             if ((boat.getStatus() == BoatStatusEnum.DNF) || (boat.getStatus() == BoatStatusEnum.PRESTART) || (boat.getCurrentLeg().getLegNumber() < 0)) {
 
-                boat.setPosition("-");
+                boat.setPlacing("-");
 
             } else {
-                boat.setPosition(Integer.toString(i + 1));
+                boat.setPlacing(Integer.toString(i + 1));
             }
         }