Removes document_root argument from django.contrib.staticfiles.views.serve

This argument can be removed, because the new way of finding static files doesn't take document_root into account at all.
Merge pull request #758 from FakoTB/master

Fixed #19572 - Remove document_root argument from staticfiles views.
Fixed #17094 - Typo in class-based views doc.

Thanks alej0 for the report.
Merge pull request #759 from erikr/master

Fix #17751: Added stripping of whitespace for IPAddressField/GenericIPAddressField
Fixed embarrassing typo in last commit.
Used token.split_contents() for tokenisation in template tags accepting variables.

Fixed #6271, #18260.
Changed "mysite/mytemplates/" -> "mysite/templates" in tutorial.

Thanks James Pic.
Fixed #19887 - Noted when callables may be used in ModelAdmin.fields and ModelAdmin.fieldset.

Thanks Patrick Strasser for the suggestion and Zbigniew Siciarz for the patch.
Fixed #19816: pre-evaluate queryset on m2m set

In ReverseManyRelatedObjectsDescriptor.__set__, evaluate possible
queryset to avoid problems when clear() would touch data this queryset
returns.
Merge pull request #769 from oinopion/ticket19816

Fixed #19816 -- pre-evaluate queryset on m2m set
Fixed #19675 - Added mention of static files to overview.

Thanks Dwight Gunning for the patch.
Fixed #17906 - Autoescaping {% cycle %} and {% firstof %} templatetags.

This commit adds "future" version of these two tags with auto-escaping
enabled.
Updated static file example in overview to use static template tag, refs #19675.

Thanks jezdez for the note.
Fixed #19752 - Changed Postgres version numbers to 9.x to avoid having to update them each minor release.
#18899 FileSystemStorage.save should support any file-like objects
Merge pull request #751 from bmispelon/ticket-6271
Fixed regression introduced in 146ed13a.

As override_settings was used after the initialization of the session backend,
we need to use a new session backend here.
Fixed #19811 - Added language code fallback in get_language_info.
Merge pull request #775 from HiddenData/ticket-18899

Fixed #18899 -- FileSystemStorage.save should support any file-like objects
Updated example to use staticfiles static template tag, thanks reinout for the suggestion, refs #19675.