added method Tile.isSteppable() for obvious reasons...

cicaprojekt/Gap.java

@@ -5,6 +5,12 @@ public class Gap extends cicaprojekt.Tile {
         super();
     }
 
+    @Override
+    public boolean isSteppable()
+    {
+        return true;
+    }
+
     @Override
     public void spawnStargate(cicaprojekt.Stargate stargate, Direction direction) {
         adjacentTile.get(direction).spawnStargate(stargate, direction);