Django-popup-field

- add context_for_all in PopupCRUDViewSet

- add class_name、class_verbose_name in PopupCRUDViewSet
- remove popup_name inside create and update url
- custom context for create and update
- custom popup title and url name

- add default POPUP_TEMPLATE_NAME_CREATE、POPUP_TEMPLATE_NAME_UPDATE in setting
- add template_name_fk、template_name_m2m in PopupCRUDViewSet
- add parent_class in PopupCRUDViewSet

- compatible with django 1.x
- change viewset achieve logic

- allow custom template_name for popup_field

- add gif and demo site