Updating product pages to be preorder-ready!

Adds in content for taking preorders (#63), using trycelery.com.
Orders are processed using their 3rd party overlay checkout system.
Also adds meta tags (#45).
Also includes new Sadarghat popover page.

![image](https://cloud.githubusercontent.com/assets/1689222/4175441/8c242078-35d2-11e4-926d-5fc3fbc183e2.png)