When creating a new language title for an existing page, do not update the slug on the other languages
Handle Title.DoesNotExist when fallback=False is used
test case for adding new language versions of existing pages
python 2.5 support for with statement
use assertRaises instead
use api.create_page instead of client.post
Merge pull request #1604 from benjaoming/support/2.3.x

Fix slug bug when creating a new language