API-CHANGES: Class hierarchy using traits.

API-CHANGES.txt

@@ -1,13 +1,10 @@
-0.19.0:
+0.18.6:
 
 * Remove class Thenable, add trait TThenable.
+* Behavior / Trait hierarchy uses traits.
 
 + NativeFunction class >>
   + isNativeFunction:
-
-
-0.18.6:
-
 + IRInstructions >>
   + isSelf
   + isSuper