currently, roundup does not send "Expires" header or 
response with a 304 to If-Modified-Since requests. This 
leads to reloading of static resources on every page 
serve. An easy workaround would be to add a Cache-
control header to static responses. For example, add 
the following line to Client.serve_static_file():

self.additional_headers['Cache-control'] = "max-
age=7200"