Removed backwards-compatibility shim for #16288.

Also unit-tested django.utils.log.RequireDebugTrue for consistency.
Removed django.conf.urls.defaults.
Removed interpolation of post_url_continue in the admin.
Removed django.contrib.databrowse.

RIP -- you served us well.
Removed the legacy form wizard.
Removed legacy shortcut for importing GeoIP.
Removed django.contrib.localflavor.

Each localflavor lives on as a separate app.
Removed django.contrib.markup.
Removed django.core.cache.backends.memcached.CacheClass.
Removed django.core.management.setup_environ and execute_manager.
Removed HttpRequest.raw_post_data.
Removed IGNORABLE_404_STARTS/ENDS settings.
Removed support is_safe and needs_autoescape as function attributes.
Removed obsolete compatibility functions for old Pythons.
Removed truncate_words and truncate_html_words.
Removed legacy ways of calling cache_page.
Removed csrf_response_exempt and csrf_view_exempt.
Advanced pending deprecation warnings.

Also added stacklevel argument, fixed #18127.
Removed versionadded/changed annotations dating back to 1.4.