To be more consistent with how access to products is handled in the
permission based dashboard, access to orders is now more permissive. As
long as one order line's partner has the current user in it's users,
access is granted.

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.

Fixes #376

Also split them into unit and functional tests.

I moved the ``OderSummaryView`` from the order section in the
dashboard to the main dashboard index and merged it with the
``IndexView``. I removed the summary template and merged the
relevant data into the dashboard template.

This allows the flow of statuses for an order to be controlled.