Marks display correctly on the canvas, no double ups or anything like that left.

#[issue10]

src/main/java/seng302/models/mark/MarkGroup.java

@@ -90,6 +90,7 @@ public class MarkGroup extends Group {
     {
         if (mainMark.getMarkType() == MarkType.SINGLE_MARK) {
             Circle markCircle = (Circle) super.getChildren().get(0);
+
             markCircle.setCenterX(x);
             markCircle.setCenterY(y);
         } else {