Supplier view update

For foodcoops not using deliveries, the deliveries list in the supplier screen is confusing. This change
* Only shows deliveries when there are any
* Shows recent orders, if there are
* Adds buttons for articles and stock articles (just in case someone didn't find it in the supplier overview).
![supplier_ui](https://f.cloud.github.com/assets/503804/2209787/ae6346ac-9990-11e3-8df2-db1327ac7c92.png)