fixed fork 'all' callback behavior

Author: dauglyon

src/Context_Nodes.js

@@ -240,10 +240,11 @@ export class Fork_Node extends Context_Node{
                 var task = new Task(forked_key, key);
                 forked_key+=1;
                 self.addTask(task);
-                task.complete(newDatum);
+                task.stored_result = newDatum;
                 newTasks.push(task);
             });
             newTasks.forEach(function(task){
+                task.complete(task.stored_result);
                 self.publishResult(task);
             });
         });