Support proxying 301 redirects

[vojtajina]

Proxy should rewrite "Location" header.

It might be implemented inside https://github.com/nodejitsu/node-http-proxy, however it does not have the information about the hostname, so we would have to pass it in as a config option.

Based on https://groups.google.com/forum/?fromgroups=#!searchin/testacular/django/testacular/kLqUOWqD3As/UP0fzADkuQIJ

[vojtajina]

Directly:

curl -I localhost:9090/search
HTTP/1.0 301 MOVED PERMANENTLY
Date: Wed, 13 Feb 2013 13:11:55 GMT
Server: WSGIServer/0.1 Python/2.7.1
Content-Type: text/html; charset=utf-8
Location: http://localhost:9090/search/

Through Testacular:

$ curl -I localhost:9876/search
HTTP/1.1 301 Moved Permanently
date: Wed, 13 Feb 2013 13:11:50 GMT
server: WSGIServer/0.1 Python/2.7.1
content-type: text/html; charset=utf-8
location: http://localhost:9090/search/
Connection: keep-alive

[vojtajina]

Closing, duplicate of https://github.com/testacular/testacular/issues/127