SuspiciousOperations have been differentiated into subclasses, and
are now logged to a 'django.security.*' logger. SuspiciousOperations
that reach django.core.handlers.base.BaseHandler will now return a 400
instead of a 500.
Thanks to tiwoc for the report, and Carl Meyer and Donald Stufft
for review.
Replaced them with per-database options, for proper multi-db support.
Also toned down the recommendation to tie transactions to HTTP requests.
Thanks Jeremy for sharing his experience.
