This closes kriskowal/q-io/issues/77. Instead of host the hostname is pa...

This closes kriskowal/q-io/issues/77. Instead of host the hostname is passed to http.request and headers.host is now the host, not hostname.

Background info:
- hostname: To support url.parse() hostname is preferred over host. Source: http://nodejs.org/api/http.html#http_http_request_options_callback
- host should include port number. Source: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.23