This allows updating code in both places, if necessary. Getting Django
1.5 support would be painful otherwise. This also removes the circular
dependency of django-oscar-testsupport on Oscar.

The requirements were merged. The imports were updated
accordingly. Unused imports in the touched files were removed. No
further changes.

Following guidance from Tangent's UX team (blame them!)

* Split 'metadata' step into 'name and description' and 'restrictions'
* Add progress bar
* Add summary of entered data in right-hand sidebar
* Clean up breadcrumbs and URLs

Still needs from FED love.

Fixes #376

Also split them into unit and functional tests.