This is a preparatory commit for using isort for sorting all of our
imports, merging changes to files where we can easily review the
changes as something we're happy with.
These are also files with relatively little active development, which
means we don't expect much merge conflict risk from these changes.
This changes the requirements for UserProfile to disallow some
additional characters, with the overall goal of being able to use
formataddr in send_mail.py.
We don't need to be particularly careful in the database migration,
because user full_names are not required to be unique.
Tim Abbott
Conner Bondurant