Added initial cut at serialization framework, along with some basic tests and...

Added initial cut at serialization framework, along with some basic tests and a stab at some docs.  This is all a bit rough right now, so expect some bumps.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@3225 bcc190cf-cafb-0310-a4f2-bffc1f526a37