created a proper add user utility to work with PAS, refs #875
work around the reg tool and only create dexterity members directly, refs #875
Remove decoy PersonAdder. Nice idea, but it won't work.
Lowercase the email in AddPersonForm. Restore the call to portal_registration.addMember().

This still doesn't explain the bizarre behavior of login_next(), sadly.
Send the response from login_next() to the browser.
Add an upgrade step to normalize email case.

Ref #875.
Ticket #901: Made it possible to remove an external media URL.

Note: several other fields appear to suffer from the same issue.  I'll start a discussion about the other fields in the ticket.
Issue #876: don't let social logins hijack accounts through unverified email addresses.
Merge branch 'membrane-person-cleanup'