Cleaned up the Memcached cache backend doc

Consistent casing, minor typo fixes, reduced rhetoric.
Fixed #23638 -- Prevented crash while parsing invalid cookie content

Thanks Philip Gatt for the report and Tim Graham for the review.
Fixed #23534 -- Added documentation on blocktrans tags

Mentioned that other block tags are not allowed inside
a blocktrans template tag.

Thanks to edu2004eu for reporting the issue.
Adapted invalid cookie test to all Python versions

Refs #23638. Older Python versions are less strict when parsing
invalid cookie content. The test just has to ensure Django doesn't
crash.
Clarified documentation relating to usage of serialized_rollback for certain classes
Fixed #23651 -- Isolated non-existent fixture tests

Previous versions of the tests were buggy, as initial_data.json
did exist and the test wasn't failing. It was finally failing on
Python 3.4.2.
Thanks Raphaël Hertzog for the report (and Debian bug #765117
contributors).
Fixed #23637 -- Removed TUX, lighttpd, and Cherokee as common.
Merge pull request #3370 from collinanderson/ticket_23637

Fixed #23637 -- Removed TUX, lighttpd, and Cherokee as common.
Added unicode_literals to the jslexer.

This ensure that ''.join(c) in jslex.py always returns text.
Fixed remaining test failure in jslex tests.
Added Bashar Al-Abdulhadi to AUTHORS

made django 100% arabized https://www.transifex.com/projects/p/django/language/ar/ , https://twitter.com/_Bashar/status/468845303668695040
Fixed #19508 -- Implemented uri_to_iri as per RFC.

Thanks Loic Bistuer for helping in shaping the patch and Claude Paroz
for the review.
Merge pull request #3373 from Bashar/patch-1

Added Bashar Al-Abdulhadi to AUTHORS
Fixed #23660 -- Moved sort_dependencies to core.
Fixed a flake8 warning.
Fixed pep8 in docs/topics/logging.txt
Fixed #23659 -- Kept annotate() args ordering

Thanks Loic Bistuer and Simon Charette for the review.
Fixed #23579 -- Changed GEOSGeometry.__str__ to include the SRID

Thanks Tim Graham for the review.
Fixed #23664 -- Provided a consistent definition for OrderedSet.__bool__

This also defines QuerySet.__bool__ for consistency though this should not have any consequence as bool(qs) used to fallback on QuerySet.__len__ in Py3.
Fixed IRC channel name in submitting-patches.txt.

The development channel is #django-dev.