part refactors email sending into a more object-oriented interface in order to
make adding new features possible without making the API unusable. Thanks to
Gary Wilson for doing the design thinking and initial coding on this.
Includes documentation addition, but it probably needs a rewrite/edit, since
I'm not very happy with it at the moment.
git-svn-id: http://code.djangoproject.com/svn/django/trunk@5141 bcc190cf-cafb-0310-a4f2-bffc1f526a37