Sinatra Named Routes w/ Subdomain support

Based on sinatra-named-routes by ckhampus: https://github.com/ckhampus/sinatra-named-routes.

Subdomain Usage

map :named_route, '/myroute/:some_id'
url( :named_route, true, :some_id => 123, :subdomain => 'mysubdomain' )

http://mysubdomain.myhost.com/myroute/123