The package network-2.4.1.1 thoughlessly introduced a backward incompatible
change to the function Network.URI.unEscapeString, see
https://github.com/haskell/network/commit/f2168b1f8978b4ad9c504e545755f0795ac869ce
This also affects the function Network.Shed.Httpd.queryToArguments, which is
used in GFServer.hs.
To remain compatible with older and newer versions of the network package,
we need to stay clear of queryToArguments and unEscapeString. A replacement
function has been added to server/URLEncoding.hs.
hallgren