In web proxies, add X-{Forwarded-{Host,Proto},Real-IP} and 'proxy_set_header Host' when there is a flag
In web proxies, add X-{Forwarded-{Host,Proto},Real-IP} and 'proxy_set_header Host' when there is a flag

Merges #1432, more or less.

mail-in-a-box/mailinabox,mail-in-a-box/mailinabox,mail-in-a-box/mailinabox,mail-in-a-box/mailinabox