This speeds up the timesince function/filter substantially.

Thanks Mark Tranchant for the report an Tim Graham for the test and
review.

Since a4b8a4b6 the admin
URL returned by get_admin_url() is no longer relative to
the Django admin index page.

Used shorter column names to make the generated index name
fit within Oracle's limit of 30 characters

Failing in a middleware `__init__` is preventing proper debug view.

Added table_name back to _create_index_sql() to prevent
duplicate index names on MySQL.

4468c08d replaced a lot of the old `dict()` comprehensions
with the new style, but missed this one.

Besides the directories they look in, these two loaders are functionally
the same. This removes unnecessary code duplication between the two.

Thanks Marcin Wrobel for the initial patch.

Follow-up of f4f24d30.

This reverts commit 9f1dbe29.
The proposed solution does not pass the test suite.

Thanks Thomas Tanner for the report.

Thanks Tomasz Kontusz for the report, Baptiste Mispelon for
analysis and Tim Graham for the review.

Thanks Johannes Lerch for the report, Tim Graham for the test case,
and Simon Charette for the review.

That line was inconveniently introduced by the committer (me) in
3b966c2b. Sorry!

The SelectFilter widget used href to execute javascript. This was
problematic if one wishes to customize the widget, since the href
javascript is executed after events are handled. This change modifies
the javascript to use click events to handle button behavior.

This reverts commit 0af3822d.
It's obsoleted by refs #24395.