Added support for Tornado's HTTPServer "xheader" setting.
If xheaders is True, we support the X-Real-Ip and X-Scheme headers, which override the remote IP and HTTP scheme for all requests. These headers are useful when running Tornado behind a reverse proxy or load balancer.
Fixed typo in command description
Merge pull request #91 from yulis/master

Support X-Real-Ip and X-Scheme headers