Make amazon_inline_item another type of amazon_item so preprocessing is done

Issue Summary

Probably for historical reasons, the amazon_inline_item is a completely separate type from all the other wonderful themed types. So the amazon_preprocess_amazon_item() doesn't get run on it. And of course, that means that amazon_store doesn't get a chance to update the link in it to point to amazon_store's namespace.

Can amazon_inline_item become amazon_item_inline and get processed with the rest?

Thanks,
-Randy