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.
Minor cleanup in the check_framework test package.
Fixed #23615 -- Validate that a Model instance's "check" attribute is a method.

The "check" name is a reserved word used by Django's check framework,
and cannot be redefined as something else other than a method, or the check
framework will raise an error.

This change amends the django.core.checks.model_check.check_all_models()
function, so that it verifies that a model instance's attribute "check"
is actually a method. This new check is assigned the id "models.E020".
Made some changes