Updated to match API changes in Beta3.

InvocationRegistration had a constructor called Registration. I wonder if
that was causing the compile error with beta2.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@4104 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/as/com/threerings/presents/dobj/InvocationNotificationEvent.as

@@ -21,11 +21,11 @@
 
 package com.threerings.presents.dobj {
 
-import flash.util.StringBuilder;
-
 import com.threerings.io.ObjectInputStream;
 import com.threerings.io.ObjectOutputStream;
 
+import com.threerings.util.StringBuilder;
+
 /**
  * Used to dispatch an invocation notification from the server to a
  * client.