Added trytond-gift-card as a dependency #6000

![gift_card_webshop-1](https://cloud.githubusercontent.com/assets/3972835/4958246/8e97b6fc-66ac-11e4-880d-334ee256a6e2.png)
![gift_card_webshop-2](https://cloud.githubusercontent.com/assets/3972835/4958250/945f6e54-66ac-11e4-9946-8961f2a9e2cd.png)