Merge pull request #629 from marisaleung/develop

ChangeBlock uses id's of variable instead of name.

src/engine/runtime.js

@@ -991,6 +991,14 @@ class Runtime extends EventEmitter {
         }
     }
 
+    /**
+     * Get the editing target.
+     * @return {?Target} The editing target.
+     */
+    getEditingTarget () {
+        return this._editingTarget;
+    }
+
     /**
      * Tell the runtime to request a redraw.
      * Use after a clone/sprite has completed some visible operation on the stage.