Implement V2 interfaces and remaining V1 interfaces

Also adds some tests to registry tests for V1 stuff.
Note: All *registry* tests currently pass, but as verbs are not yet converted, the verb tests in registry_tests.py currently fail.

endpoints/v1/tag.py

@@ -9,7 +9,7 @@ from auth.auth import process_auth
 from auth.permissions import (ReadRepositoryPermission,
                               ModifyRepositoryPermission)
 from data import model
-from data.model import v1
+from data.interfaces import v1
 from endpoints.common import parse_repository_name
 from endpoints.decorators import anon_protect
 from endpoints.v1 import v1_bp