Incompatable changes with zoph schema:

1. parent_album_id, parent_place_id, parent_categegory_id set to NULL if no parent, not 0.
2. many to many tables have new primary key, as Django doesn't support multi primary keys.
3. some CharFields replaced with TextField: notes (person), notes (place),
   album_description (album), category_description (category), comment (photo)
4. Django tables used for comments.
5. Replaced date (photo), time (photo) with datetime and timezone.
6. Photo contains action field.
7. Comments/rating uses django tables.
