Scrapped using a Comparable for the keys to a DSet on this side of things.

- There is no such thing as Comparable in ActionScript, I had made my own,
  but String (one of the most common keys) couldn't implement it, and String
  is a final class (like in Java). It would be a huge inconvenience to have
  to wrap String objects.
- The language also has no .equals() method in the base class. The strict
  equality operator (===) works like equals() except that objects that
  aren't one of the base types (String, Number, Boolean, int) are compared
  by reference. I added a "Equalable" interface, if the key in a DSet
  implements that interface then equals() is called, otherwise the strict
  equality operator is used.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@3897 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/as/com/threerings/presents/client/InvocationRegistration.as

@@ -31,11 +31,9 @@ public class InvocationRegistration
     }
 
     // documentation inherited from interface DSetEntry
-    public function getKey () :Comparable
+    public function getKey () :Object
     {
-        return null; // TODO receiverCode;
-        // TODO: maybe we drop the concept of Comparable and just
-        // use any old objects: screw performance
+        return receiverCode;
     }
 
     // documentation inherited