Fix "Active" class in dynamic submenu's (#512)

* Fix "Active" class in dynamic submenu's

I'm not really sure what the impact is of this change, but in my case it seem's to fix my issue.

When you use `addIn` to add sub-menu items, the top menu item doesn't get the active class as it should.

* Cleanup. Fix TravisCI

src/Menu/Builder.php

@@ -123,7 +123,7 @@ protected function addItem($itemKey, $direction, ...$newItems)
                     array_splice($menuItems, $lastKey + ($direction == 'after' ? 1 : 0), 0, $items);
                 }
 
-                Arr::set($this->menu, $arrayPath, $menuItems);
+                Arr::set($this->menu, $arrayPath, $this->applyFilters($menuItems));
             }
         }
     }