Fix requirements.txt.
Fix adding users through the admin interface.
Return 404 for non-existing item.
Update idea config, new versions of django*.
Show error when vendor has no barcodes.
Rename Seller -> Vendor
Rename Cleric -> Clerk
Add some development initial data.
Fix column id.
Rename Registry -> Checkout.
Add event selection to barcode listing.
Add separate errors for inputs of barcode listing.
Add line-ends to terminal url regexps.

- This ensures that parameters are not ignored if they do not match the
  regexp.

Conflicts:
	kirppu/app/urls.py
Implement vendor login.
Fix requirements.txt.
Implement user logout.
Change test fixture paths to be platform neutral.

- This allows tests to pass on Windows.
Remove the Event model.

Updated other models, views, urls, admins, templates and fixtures
accordingly.
Implement vendor sign up.
Fix problems with util.py and add tests.