Fix csv upload

Fixed problem of uploading null values in int fields of the datastore
Change couple class and Eatery class

Add way to confirm P2 user in couple class, and set a Couple entity as
the ancestor of each Eatery
Add memcache of Hitlist and Eatery

Added functions to cache Hitlist and changed process csv function to
cache Eatery objects
Change cache_entity

Added parent_key argument to entity query to ensure consistency