Django-shopit

* Fix setup requirement.

* Drop `Django 1.10` support.
* In `ProductDetailView`, check for renderer format before adding django-cms menu related items.
* Remove `PhoneNumberField` from the project, use simple `CharField` instead.
* Lock requirements.

* Rename package from `djangoshop-shopit` to `django-shopit`.

* Fix encoding error in product admin `get_name` method.
* Add `phonenumbers` library to requirements.

* Fixes 7 - "unhashable type: 'MoneyInEUR'" error in `get_price_steps` templatetag.

* Small fixes in admin.
* Fix indentation in admin help text for ``djangocms-admin-style``.
* Refactor tests.