Feature/717 read api

It's not a stub. The method will be executed on an unauthorized access attempt. In the case of browser access this method redirects to the [login page](https://github.com/akvo/akvo-flow/blob/develop/GAE/src/org/waterforpeople/mapping/app/web/rest/security/GoogleAccountsAuthenticationEntryPoint.java#L23), but for `/api/v1` access we simply return status 401 instead. I can look into if it's possible to not have an entry point at all in this case.