* Add changes for django 2.0
Made the following changes to ensure compatibility with django 2.0:
1. Replaced function calls to `is_authenticated()` with reference to
property `is_authenticated`.
2. Added try/except call to import `django.core.urlresolvers` (now
called `django.urls`.
Also added an `... as ...` statement to ensure that references in the
code to `urlresolvers` don't need to be changed.
3. Fixed calls statement of `on_delete` arg to all ForeignKey
fields.
Note that previously a kwarg was acceptable, but this is now a
positional arg, and the selected `on_delete` method has been
retained.
* Update tox tests and consequentual changes
Updated tox.ini to also test django 2.0 on python 3+. Some changes made
to previous commits required to ensure all tests passed:
- Added `compat.py` to have a `is_authenticated()` function to check
authentication.
This was necessary as the property/method call for `is_authenticated`
is no compatible between django 1.8 (LTS) and 2.0.
Changed AuditLogMiddleware to call this compatibility function instead
of the django built-ins as a result.
- Changes made to `auditlog/models.py` to apply kwargs to both `to=` and
`on_delete=` for consistency of handling in all version tested.
Incorrect django version specified for tox.ini. Now fixed.
* Add 'on_delete' kwarg to initial migration
Added and re-arranged 'on_delete' and 'to' kwargs in initial migration
to ensure compatbility with later versions of Django.
Also included updated manifest with changes required due to django 2.0
work.
* Add TestCase for compat.py
Added simple test case for compat.py file.
* Changes follow code review 2017-12-21
* More changes following code review 2017-12-28
1. Added detailed commentary to `compat.py` to ensure reason why
`is_authenticated()` compatibility function is needed
2. Changed `hasattr` to `callable` in compat.is_authenticated()
3. Fixed typo in migration 0001 to use correct `on_delete` function
