Rename the host condition method to host_name to match Sinatra #35
Description
Sinatra has defined a host_name condition method since 2.0.0. Plus by defining our own host condition method it overrides the App's host setting. We should rename host to host_name to match Sinatra's API. Even though ronin-web-server and Sinatra's versions of host_name would be identical, we would control the method and have YARD documentation for it.