Fixed #22392 -- Corrected deployment instructions for Apache 2.4.

Thanks zjcheah at yahoo.com for the report.
Fixed #22443 -- Document smtp.EmailBackend.timeout default value

Django 1.7 introduces a new timeout parameter for the SMTP email backend:
http://docs.djangoproject.com/en/dev/topics/email/#django.core.mail.backends.smtp.EmailBackend.timeout

However, there was no mention of the default value for this parameter.
Added RemoteUserMiddleware to middleware reference page.
Added a note regarding django.contrib.auth.authenticate.

Thanks Josh Brown for the suggestion.
Fixed #22453 -- Corrected DoesNotExist message in docs.

Thanks Eugenio Cano-Manuel.
Fixed #22457 -- Fixed contributing guide w/o github set-up

The published commnand was not working when the user did not have
the git client set-up with the public-key. Changed the contributing
guide to clone it from https instead.
Fixed spelling errors in documentation.
Fixed #22353 -- Make sure that CachedStaticFilesMixin doesn't use invalid cache entries instead hash the actual file.