match .nested-inline margin to td margin
match .nested-inline margin to td margin

This way, the margin/padding is consistent across nested tabular and stacked groups.
APSL/django-nested-inline,Dmitri-Sintsov/django-nested-inline,anshumanb/django-nested-inline,anshumanb/django-nested-inline,anshumanb/django-nested-inline,s-block/django-nested-inline,APSL/django-nested-inline,s-block/django-nested-inline,Dmitri-Sintsov/django-nested-inline,APSL/django-nested-inline,Dmitri-Sintsov/django-nested-inline,s-block/django-nested-inline