Reset collision tag on visualiser boat after displaying collision

- Modified View3D to index subjects rather than shapes by source ID
- Enforced one collision per boat on server to reduce rendering load
- Changed collision radius to less than bounce radius
- Fixed game-breaking null command bug

#story[1195]

racevisionGame/src/main/java/visualiser/layout/View3D.java

@@ -36,9 +36,9 @@ public class View3D extends Pane {
      */
     private Map<Shape3D, Subject3D> shapeMap;
     /**
-     * Map for selecting Shape3D from source ID
+     * Map for selecting Subject3D from source ID
      */
-    private Map<Integer, Shape3D> sourceMap;
+    private Map<Integer, Subject3D> sourceMap;
     /**
      * Subject tracked by camera
      */
@@ -150,14 +150,14 @@ public class View3D extends Pane {
                     for (Subject3D shape : c.getAddedSubList()) {
                         world.getChildren().add(shape.getMesh());
                         shapeMap.put(shape.getMesh(), shape);
-                        sourceMap.put(shape.getSourceID(), shape.getMesh());
+                        sourceMap.put(shape.getSourceID(), shape);
                     }
                 }
             }
         });
     }
 
-    public Shape3D getShape(int sourceID) {
+    public Subject3D getShape(int sourceID) {
         return sourceMap.get(sourceID);
     }