Added setup command and made lookup work sanely. #15

The setup command loads the default data into a default location, then
creates a whoosh index in a default location.

get_index is now open_index and can be made to explicitly recreate the
index.  It also actually opens the index if it already existed, even
across processes, now that FileStorage is working.

The lookup command takes no switches for aiming at a different database;
it only uses the default data stores.