Browse.html styling

Modified the abstract_models.py to get product.is_available_to_buy working properly (Moose told me to add it.)

browse.html page styling and pulling correct data, 

Styled category description and image

Started work on the detail.html page

![Screen shot 2013-04-12 at 4 50 29 PM](https://f.cloud.github.com/assets/726265/371701/eb6c8fe4-a342-11e2-88fb-129b2f0a1fa3.png)