Made sure that removed events for grouped objects are fired when grou…

…p is removed

src/shapes/group.class.js

@@ -100,8 +100,19 @@
       }
 
       this.setCoords();
+      this.on('removed', this._objectCleanup);
     },
 
+    /**
+     * @private
+     */
+    _objectCleanup: function(){
+      while(this._objects.length){
+        this.remove(this._objects[0]);
+      }
+    },
+
+
     /**
      * @private
      * @param {Boolean} [skipCoordsChange] if true, coordinates of objects enclosed in a group do not change