Introduced django_extra_patterns
This way no classes ever need to override the getDjangoURLPatterns,
which results in less code, which is also more clear (that is, it is
immediately obvious that a View adds an extra mapping if it sets
the new django_extra_patterns value, or that it overrides the mapping
when it sets django_patterns_defaults.
Patch by: Sverre Rabbelier
from query import *
from subqueries import *
from where import AND, OR
from datastructures import EmptyResultSet
__all__ = ['Query', 'AND', 'OR', 'EmptyResultSet']