an extremely brutish workaround for issues such as #110 where
browsers receive an HTTP 304 and misinterpret as HTTP 200
option `--no304=1` adds the button `no304` to the controlpanel
which can be enabled to force-disable caching in that browser
the button is default-disabled; by specifying `--no304=2`
instead of `--no304=1` the button becomes default-enabled
can also always be enabled by accessing `/?setck=no304=y`
ed