Do not add an empty menu item

Before
![1](https://cloud.githubusercontent.com/assets/1333220/4794248/7313d88c-5df3-11e4-89db-27f8d041c814.png)
After
![2](https://cloud.githubusercontent.com/assets/1333220/4794249/7748e33e-5df3-11e4-9c8c-02d0698e55d4.png)

`if(!item.title) return;`