[autopep8] Fix coding style.

biscuit/core/forms.py

biscuit/core/migrations/0001_initial.py

biscuit/core/migrations/0002_fill_person_model.py

biscuit/core/migrations/0003_split_person_user.py

biscuit/core/migrations/0004_group.py

biscuit/core/migrations/0006_make_unique.py

biscuit/core/migrations/0008_school_person_group.py

biscuit/core/migrations/0010_user_one_to_one.py

biscuit/core/migrations/0011_default_school.py

biscuit/core/migrations/0012_allow_null.py

biscuit/core/migrations/0013_person_primary_group.py

biscuit/core/migrations/0015_person_photo_crop.py

biscuit/core/models.py

biscuit/core/util/core_helpers.py

biscuit/core/views.py