TODO:
/**
* Get product information
*
* @example
*
* {product post_id="{$post.ID}" assign_to="product_info"}
*
* <h1 itemprop="name" class="product_title entry-title">{$post.post_title}</h1>
* <p class="price"><span class="amount">${$post.price}</span></p>
*
* <div class="product_meta">
* <span class="posted_in">Categories:
* {foreach $product_info.data.categories as $cat}
* <a href="{$cat.permalink}" rel="tag">{$cat.name}</a>{if !$cat@last}, {/if}
* {/foreach}</span>
* </div>
*
*/