Crawler: better redirect handling
Crawler: better redirect handling

The test client followed URLs; now it passes the final redirect_chain to
_parse_urls so relative URLs are joined correctly (i.e. if "/foo"
redirects to "/foo/" we want <a href="bar"> to become "/foo/bar", not
"/foobar").

acdha/django-test-utils,ericholscher/django-test-utils,ericholscher/django-test-utils,acdha/django-test-utils,frac/django-test-utils,frac/django-test-utils