Fix product view template to render well and allow 5 thumbnails on a lin...

...e

I've fixed CSS and media format to render well on product template depending on screen resolution:

![capture decran 2014-01-27 a 10 24 34](https://f.cloud.github.com/assets/103900/2007273/e607dae6-8734-11e3-95a4-f4b494571098.png)

![capture decran 2014-01-27 a 10 21 08](https://f.cloud.github.com/assets/103900/2007258/a7eb0012-8734-11e3-81f7-4ff6bbe19076.png)