Support general items (not just books)

[richard-jones]

To support items other than books we need to:

• update the data and object models to include a "category" and a "description"
• add a new facet for the category to the search interface
• provide a full category listing (similar to the Browse by Subject for books #66 )
• Create auto-complete endpoint for categories
• Create a search result layout for non-Book categories.

Non-Book categories will contain only the following data:

• Title
• Description
• Picture
• Category
• Price
• Location

The "Selling an item" page will be updated as follows:

1. The user will be presented with two radio buttons "Book" and "Other".
2. Selecting "Book" will present the book entry form (see #49 )
3. Selecting "Other" will present the general entry form. This form will present only the fields listed above, and the Category field will be an auto-complete which draws on the existing categories and allows the creation of new ones ad hoc.

[mjb295]

This looks about right, but we should also add "condition" as an option for non books.

[richard-jones]

There is now system wide support for objects other than books.