Display ct fields referenced by category term.

[kenorb]

1. Edit term and set Content Type(s) (or use /admin/structure/taxonomy_manager/voc/categories/346).
2. Enable display for 'Category node references' (field_ad_category_node_ref) at /admin/structure/types/manage/advert/display
3. Go to add ad form and select that category.
4. On 2nd page, you should see fields provided by ct defined in field_ad_category_node_ref field.

Probably we need to define our Display format to display such fields.