Put v1 api into separate file to keep it around.

It is not needed b/c api-v1 will not be changed.
Added corresponding fixtures to api-v1.
Updated test fixtures.
Returning Content-Type as 'application/json'.
Now sending cards with users.
Lowercased card's UserId to user_id.
Changed description.
More test for GET /users.
Added method for 200 responses.
Added helper for 400 responses.
getPublicModels can now handle single objects.
Added optional status parameter to sendPublicModels.
Added POST /users.
Added tests for POST /users.