Expose not only db but also conn to in-mem db.

This is mostly for playing around in a repl, but it's useful.
Add helpers for summarized and full recipes.

This could be an optimization (don't know), but it's mostly due to the
fact that `d/entity` returns a lazy map and we want only some attributes
in some places and all attributes in other places.

So `with-fields`, `summarize` and `full` it is!
Support querying for multiple attributes.

Now this is something I really like. It's natural, quite short and
should map beautifully to maps gotten from arguments to routes.
Add helper to convert results of a query to entities.
Add mantras.

Fun is better than features.
Expose defined attributes as separate map.
Support for queries.

Whew, that was interesting. Would like to know if querying for multiple
ingredients works, but that's for later. After some cleanup and
clarifying a few weird things (why does `find-all` display any keys at
all, is this cheshire using `keys` on it?).
Add a category for testing the queries.