Split `VerifyEmailMixin` and `BasicUserFieldsMixin` into more mixins.
Move check to EmailVerifyUserMixin
Fix syntax for python2
Move `__str__` and `UserManager` on `NameUserMixin`
Mixin order matter
Update CHANGELOG.md
Fix test with unicode
Simplify test with Python2AssertMixin
Update class definitions.
Merge pull request #86 from incuna/split-mixins-into-mixins

Split mixins between fields and methods