Fixes #2547.

Refs #2567 - the changes made there fail if the stock record
belongs to a child product.

There is a subtle change in behaviour here. Null is converted to ''
only when reading the field value from the database. Previously
this was done in the to_python method, but this causes problems
with uniqueness validation.

* Silently skip stock allocation manipulations if the product class doesn't track stock.

* Make it possible to cancel/consume stock allocations without line args.

You can now do:
consume_stock_allocations(order)
cancel_stock_allocations(order)
without the lines / line_quantities arguments.

Previously, validation did not pass when current locale is "en-gb" and URL is "/de/catalogue/" and visa versa due to default Django URL resolvers behaviour  - they do not take into account all locales, only current.

Also fix the max_length on the url field. The underlying model field has
a max_length of 100, so it is invalid to have a larger value here.

DRY out dashboard page update/create views.

Refactor tests - perform tests of form logic directly rather than indirectly through view code.

Fixes #2559.

Fixes #2526.

phone_number_fields is more correct grammatically.

Add to the dosctring for the class, and display it in the documentation.

With this change phone numbers (any qty) can be added as `ModelForm`
property `phone_numbers_fields` - dict where "keys" are names of
phone numbers fields and "values" are attributes of fields.

* `PhoneNumberMixin` clightly reworked and moved
from `oscar.views.generic` to `oscar.forms.mixins`
* Couple tests added (based on previous tests)

The priority isn't strictly a "restriction", but this seems like the most sensible form to add it to.

If a url_name is invalid, then log the exception instead of silently discarding that menu item.

Notification subjects have a max length of 255 characters, which can easily be exceeded by long product names. Change the alert logic to provide a short notification subject and put the longer content in the notification body.

This patch also modifies the notification utils to make it obvious that the positional argument is a notification subject, not a body.

* flesh-out initial opaque data-model

refactors the basket line consumption into a facade object.

the goals is accomodating combitions of various offers on the same basket-lines,
while remaining backward compatible with the current single offer per line
policy.

* add docstrings

* add exclusive flag to conditionaloffer model and continue refactoring

* test new offer consumption on basket view

* cleanups

* fix exclusivity

* code style

* add cast to pacify tests

* spelling

* add some documentation to the release notes

* move documentation to new 1.6 release docs

Fixes #2414.

This reverts commit 9f74ef94e7. The related bug was fixed in Django 1.11.4

Subsequent views of the page (for the same order) should not trigger an event.

Fixes #2413.

This is to prevent the possibility of spamming a user by generating lots of alert confirmation emails for product alerts.

Also allow unconfirmed alerts to be cancelled - we send a cancellation link in the confirmation email, so we should let users cancel an alert if they don't want to confirm it.

Fixes #2401.

- When tax is known but zero, line_tax should return Decimal(0).
- When tax is not known, line_tax should return None.

Fixes #2395.

* Add datetime attribute to ProductAttributeValue as asked for in issue #2389

Used widget DateTimePickerInput from oscar.forms.widgets

* Fix migration catalogue 0012 (was error with python3)

* Add tests for ProductAttributeValue

In Python 2, adding None to the basket total worked, but in Python 3 this raises a TypeError. This fixes the handling of totals to distinguish between a zero price and a non-existent price.

* fix bug in grouped_voucher_discounts

* add test for grouped_voucher_discounts

* remove 3.6.1 syntax

* improve test

- Refactor clean methods to return all validation errors, rather than just the first one we found.
- Fix clean method type errors in Python 3
- Add tests for the clean methods for all benefit types.