Fixed #7177 -- Added extra robustness to the escapejs filter so that all

invalid characters are correctly escaped. This avoids any chance to inject raw
HTML inside <script> tags. Thanks to Mike Wiacek for the patch and Collin Grady
for the tests.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@8577 bcc190cf-cafb-0310-a4f2-bffc1f526a37