Fixed #19319 -- Updated example httpd.conf for Apache 2.4

Thanks colinnkeenan@ for the report.
Fixed #20290 -- Allow override_settings to be nested

Refactored override_settings to store the underlying settings._wrapped
value seen at runtime, not instantiation time.
Fixed #20612 -- Fixed incorrect wording in CBV documentation

Thanks to ndokos for the report.
Fixed #19881 -- Documented that get_next/previous_by_FOO uses default manager.
Fixed #20634 - Corrected doc mistake re: staticfiles finders strategy.

Thanks claudep for the catch and bmispelon for the research.
Fixed 17478 -- Allowed queryset overriding in BaseModelFormSet init

BaseModelFormSet.forms is now a cached property instead of being
populated in the __init__ method. This behaviour also matches an
example in the documentation.
Thanks Thomasz Swiderski for the report and Simon Charette for the
review.
Fixed #18872 -- Added prefix to FormMixin

Thanks @ibustama for the initial patch and dragonsnaker for opening the
report.
Merge pull request #1294 from LuRsT/added_prefix_to_form_mixin

Fixed #18872 -- Added prefix to FormMixin