Gonna need that now that I'm actually throwing some of these across the net.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@5772 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/presents/dobj/DSet.java

@@ -75,6 +75,9 @@ public class DSet<E extends DSet.Entry>
      */
     public static class KeyWrapper<T extends Comparable<?>> implements DSet.Entry
     {
+        // Zero arg constructor for unserialization
+        public KeyWrapper () { }
+
         public KeyWrapper (T key) {
             _key = key;
         }