Data load script.

Checking user and ownerOrg should verify that they really exist in the database (checkId just makes sure they have a valid ObjectId format).

It would also be nice to be able to specify an alias instead of an ID, e.g. that if it looks like an ObjectId then we look up on that, otherwise on the alias.  (This would need new getUserByAlias/getOrgByAlias functions, though, but it should be pretty simple.)