Added traced exception if the AppEngine login cookie isn't found
Changed the GetAuthTokenCallback to be anonymous
Comment fix
Extracted authToken to a member
Added the invalidateAuthToken method
Changed the Authenticator to a local variable
Small fix in authToken invalidation
aesthetics
Changed authenticator to member again, and added the invalidate method
Handles invalid token by invalidating it and retrying authentication
Changed progress text
Merge branch 'invalidate_auth_fix'