Fixed #20409 -- Clarified how unique_for_date works when USE_TZ is set.
Fixed #21013 -- Ensure that ModelAdmin.get_queryset is considered for the admin history view.
Fixed #21068 -- Added some docs for DiscoverRunner

Thanks jcd.
Fixed some flake8 warnings
Fixed #16869 -- BaseGenericInlineFormSet.save_new should use form's save() method

Thanks mattaustin for the report and Pablo Recio (pyriku) for the patch.
Fixed #18766 -- Pointed to pytz when LocalTimezone fails.

Thanks void for the report.
Repositioned two paragraphs in the release notes.
Removed an unused local var
Removed a ton of unused local vars
Hardened the test introduced in ded11aa6. Refs #18766.

Inputs acceptable to time.mktime are platform-dependent.
Further hardening. Refs #18766.
Removed some more unused local vars
Fix #20745: Don't silence TypeError raised inside templates.

Thanks to robin for the report and claudep for the review.
Added a test to show that the user.is_staff check in admin base.html is necessary.

refs #21067
Fixed #20889 -- Prevented email.Header from inserting newlines

Passed large maxlinelen to email.Header to prevent newlines from being
inserted into value returned by _convert_to_charset

Thanks mjl at laubach.at for the report.
Simplify FilterExpression.args_check
Add myself to authors file
Fixed #20707 -- Added explicit quota assignment to Oracle test user
To enable testing on Oracle 12c
Fixed #16895 -- Warned about cost of QuerySet ordering

Thanks outofculture at gmail.com for the suggestion.
Fixed syntax error on Python 3.2; refs #20889.