This means subclasses can override save() without needing to worry about
passing around the internal parameters (an issue for subclassable models, which
would have meant every model, since you don't know when somebody will subclass
your model).
Slightly backwards incompatible, since it moves "raw" back to being part of the
internal API (it's only needed by the serializer and was intended to be
internal use only). If external code really needs this, they can call
Model.save_base() and pass in raw there.
git-svn-id: http://code.djangoproject.com/svn/django/branches/queryset-refactor@7221 bcc190cf-cafb-0310-a4f2-bffc1f526a37
