Serve static files with HTTP::Server::Simple

 HTTP::Server::Simple::Static is a mixin that adds a method to serve
 static files from your HTTP::Server::Simple subclass.
 .
 The Date and Last-Modified HTTP headers are set when sending a response
 for a valid file. The method supports clients which send an If-Modified-Since
 HTTP header in the request, returning a 304 Not Modified response if the file
 is unchanged. If the client makes a HEAD request no message body will be
 returned in the response.