Convert test lookup to new style and add legacy format tests.
Convert test lookup to new style and add legacy format tests.

--HG--
branch : multi-field-lookups

affan2/django-selectable,makinacorpus/django-selectable,mlavin/django-selectable,affan2/django-selectable,mlavin/django-selectable,makinacorpus/django-selectable,mlavin/django-selectable,affan2/django-selectable