Add saving extra data from POST or GET to session

SOCIAL_AUTH_FIELDS_STORED_IN_SESSION has to be presented.
Merge pull request #585 from alepane21/master

Support for custom user model (django 1.5)
Added stackoverflow backend

Some of the OAuth endpoints don't return json; they return query string
encoded key value pairs. Also, the profile API call returns gzipped
content, even though urllib2 is not sending a request with the
accept-endoding of gzip.
Merge pull request #586 from chase-seibert/stackoverflow

Added stackoverflow backend
Use named kwargs to access arguments in user_data. Closes #587
Merge branch 'master' of github.com:omab/django-social-auth
Add description of ``SOCIAL_AUTH_FIELDS_STORED_IN_SESSION``
Fix rst indention
remove unnecessary South documentation, fix typos

The proposed South snippet is already in social_auth/fields.py and a "manage.py syncdb --migrate" shows social_auth as being migrated as opposed to being synced by default, so I /believe/ this is no longer necessary.
Merge pull request #588 from mrooney/patch-1

remove unnecessary South documentation, fix typos
Merge pull request #583 from marselester/save-more-than-redirect-url-to-session

Saving extra data from POST or GET to session
Updating Google OpenID, OAuth and OAuth2 documentation links.
Merge pull request #589 from JasonSanford/master

Update Google OpenID, OAuth and OAuth2 documentaion links
- worst thing doable: added my app frozen model to the migrations