Some of the Object::equals now are const correct.

There's more to do.

Why make this const-correct, instead of ditch it?  Because whatever
I replace it with has to be ready for const correctness.

lout/container.cc

@@ -313,7 +313,7 @@ int List::size ()
    return numElements;
 }
 
-bool List::equals(Object *other)
+bool List::equals(const Object *other) const
 {
    List *otherList = (List*)other;
    Node *node1 = first, *node2 = otherList->first;