Merge branch 'release/4.11.1' into develop
git_clean doesn't need to be serial. probably a copy-n-paste error.
Add a null list filter class for django admin.
flake8 happyness.
try to reactivate the emailuser form.
Move the filters to a dedicated file. EmailUser is OK, it must just not be imported if we don't want it in the current project.
Do the same for models & mixins.
Try to not make sparks models auto-imported when needing only mixins.
version bump
Merge branch 'release/4.12'