Pyramid-simpleauth

Switch the email schema to not resolve domains by default -- this avoids
a module import level dependency on dns resolution.

Add bearer token orm, repo and auth policies. Tidy up the model module.

Bump to remove `src/*.egg-info` directory from PyPI distribution.

Replace global unique constraint on `auth_emails.address` with a composite
constraint on `.address` and `.user_id`.

As a consequence, update the `model.get_existing_email` function with an
optional `user_id` parameter and update the `./prefer_email` view to use it
-- thereby making sure the preferred email belongs to the user.

Log user out after change password.

Fix test compatibility and tweak docs.