Network.URI might benefit from being separated into a different package

[bmillwood]

The Network.URI module is frequently not necessary to people who just want to open a socket of some kind, and conversely one can imagine uses of Network.URI by people who aren't interested in sockets at all (maybe CGI scripts).

With the module in the network package, the socket users have to install parsec, and the URI users have to run a configure script and C compiler etc. for what is essentially pure Haskell. Both might benefit from the Network.URI module being separated into its own package.

[singpolyma]

This should probably be closed as a duplicate of #76