Currently when super user login is passed to the UsersManager function accepting a $userLogin parameter, result is not always right.
However results are accurate when the super user token_auth is used.
We should fix implementation so that result is accurate when $userLogin is set to the super user login.
Also we should check that other API methods accepting logins are expected to receive the Super User login.
(In 1040) – fixes #582 API UsersManager.* accepting $userLogin should work well when super user login is passed
+ adding tests
- tests are much faster now: only creating/droping DB and tables once per class rather than once per method
- fixing broken test (infinite recursion in datatable calls destruct +100 times)