When X-Forwarded-For is presetn, get_address returns the whole list of IPs

[pmarques]

The get_address method needs to parse the X-Forwarded-For header and return only the first one.
It also needs to check if other headers are used, at least x-real-ip and x-client-ip.

This is critical to run applications behind proxies.

[joamag]

@pmarques nice one