Fix broken User link_name validations. Changes in r1014 still caused some problems so I came out with new idea to compare User accounts (previously called "id"). Patch by: Pawel Solyga

from query import *
from subqueries import *
from where import AND, OR
from datastructures import EmptyResultSet

__all__ = ['Query', 'AND', 'OR', 'EmptyResultSet']