Support X-Forwarded-Host, X-Forwarded-Port and X-Forwarded-Proto, to let...

Support X-Forwarded-Host, X-Forwarded-Port and X-Forwarded-Proto, to let restarting SickBeard behind a proxy work.

Without this, restart.js will redirect to the internal proto/ip/port, which may be unreachable.

This requires support from the proxy, eg:

proxy_pass http://192.168.0.1:8080;
proxy_set_header X-Forwarded-Proto https;
proxy_set_header X-Forwarded-Port 9999;
proxy_set_header X-Forwarded-Host $host;

To proxy https://host:9999/ to http://192.168.0.1:8080