Revert "Treat ModelAdmin like an old python class"
Revert "Treat ModelAdmin like an old python class"

This reverts commit 669558204e5c7c6e806ffa41a2145b9b031d2c7b.

pombredanne/django-simple-history,treyhunner/django-simple-history,emergence/django-simple-history,treyhunner/django-simple-history,pombredanne/django-simple-history,luzfcb/django-simple-history,emergence/django-simple-history,luzfcb/django-simple-history