Removed FANDJANGO_SITE_URL from TestFacebookMiddleware settings file
to break test.
Set FANDJANGO_SITE_URL default to None
get_post_authorization_redirect_url now checks that FANDJANGO_SITE_URL is set
If not defaults to request.get_host()
Fixed get_post_authorization_redirect_url assertion based on FANDJANGO_SITE_URL being absent.
Added test doc.
Made redirect url absolute
Merge pull request #99 from ademuk/fix-settings-attribute

Fix FANDJANGO_SITE_URL settings attribute