Add categories

[hatkirby]

The admin panel should have a section for creating an editing categories. Categories will have names, and will be hierarchal (pls no circular dependency). An entry can be a member of at most one category, but it does not have to be in any, so the category selection on the entry form should be a dropdown. The hierarchy of categories should be shown in this dropdown by intended "-" symbols as so:

Pokémon

• Catching Legendaries
• Rarities
• • e-Reader Cards
    Web Design

Categories should have their own editable body just like blogs that is displayed on the page for a category. The record for an entry should show the hierarchy of categories that the entry is in, with each one being linkable, and the closest one to the entry being highlighted distinctly. The page for an entry should also show what category it is in, perhaps in the breadcrumbs at the top of the page.