Change category item loading to avoid asking for primary category

In-Portal 2 major kinds of items:

• regular items
• category items

Regular item is an item, that are used a lot across In-Portal, like "user", "affiliate", "manufacturer", etc.
Category item is regular item with extra features for handling it's location inside multiple categories.

Category item can be loaded from database on demand using this code: $object->Load($link_id);
However this implies, that this item has a primary category bound to it. When it doesn't whole loading fails.

This creates a problems when developer trying to act on category item before it has been added to at least one category.