Include all expected fields in the user schemata

The expected fields are "id", "email" (optional), "firstname"
(optional), "surname" (optional), "type" (optional, defaults to cnx-id)

User "type" needs to be set to "cnx-id" for publishing to recognize the
user

Add extra validation to "authors" in document to make sure there is at
least 1 author
Add publishers to documents

Publishers is now required by cnx-publishing.

MANUAL-UPGRADE: Add a json column "publishers" to the document table in
postgres db
Add a flag in publication functional tests to allow manual testing
Merge pull request #68 from Connexions/add-user-fields

Fix authors field and add publishers to documents