Nicer display for empty categories

[Venefilyn]

Right now if a category has no entries, it will be a blank page. This is specifically for categories that themselves have no entries, but only subcategories.

I see two possibilities:

1. Do not resolve to empty categories, have a property in types.json that tells you whether it is empty or not and do not make the category item clickable.
2. Allow resolving to empty category, but display all the categories on the page as well since there are no entries in the category