Fix .bulk_create() API to comply with Django
Fix .bulk_create() API to comply with Django

Closes #130

th13f/django-cacheops,bourivouh/django-cacheops,Suor/django-cacheops,andwun/django-cacheops,ErwinJunge/django-cacheops,rutube/django-cacheops,LPgenerator/django-cacheops,whyflyru/django-cacheops