Fixed null pointer exception when a boat finishes the race.

Boats now default to have position (0, 0).
Added mark rounding data to single player race.xml

racevisionGame/src/main/java/mock/model/MockRace.java

@@ -341,7 +341,7 @@ public class MockRace extends Race {
 
             this.updateEstimatedTime(boat);
         }
-        checkPosition(boat, totalElapsedMilliseconds);
+
     }
 
     private void newOptimalVMG(MockBoat boat) {