made gae.ErrNoSuchEntity work with the new (no longer using GetLocation and GetStatus) httpcontext.Response. made the httpcontext.HandlerFunc use scopes to limit access. pushing the scope checking down to httpcontext from jsoncontext and gaecontext as well. made jsoncontext check min api version. added utils.AccessToken#Scopes() []string, and using it for the scope checking in httpcontext. made DefaultJSONContext#LoadJSON use the scopes provided by the access token. made the JSONType in the dochandler write out what fields are updatable in what scopes, and what scopes are required for the endpoint in whole.