Adding note for future enhancement.

Fil Peyton · Fil Peyton · commit 5272d208c335 · 2015-11-03T14:35:49.000-08:00
diff --git a/README.md b/README.md
@@ -40,4 +40,5 @@ syncMessage.syncMessageResponseInit(responderWindow, requesterWindowOrigin, requ
 
 ### Possible Enhancements
 * Deferred object returned from `syncMessageResponseInit`
-* Dynamic merging of original postMessage message and data returned from responder window
+* Dynamic merging of original postMessage message and data returned from responder window
+* Expand functionality to include single directional messages as well
