Fixed #20364 -Added a passing test to Chris Piwoński's set that confirms URLs in quotes followed by commas are handled correctly by his patch.
Thanks to EmilStenstrom for raising this, and to Chris Piwoński for all of the fixes and most of the tests.
Applied the urlize patch at: https://code.djangoproject.com/attachment/ticket/20364/20364.diff
Also merged the tests from: https://github.com/kriestof/django/commit/4dc7d8daa6b3ba3da3c162f3d8be9a2a17c1aae0

 On branch grg-urlize-tests
        modified:   tests/defaultfilters/tests.py
	modified:   django/utils/html.py