Used token.split_contents() for tokenisation in template tags accepting variables.

Fixed #6271, #18260.
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.
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.