Patch with new API for get/setsockopt

[Bryan O'Sullivan]

Matthew Danish wrote:

> I thought of this, but didn't go this way because I did not want to
> change the existing SocketOption type.

Sure.

> There's also some argument
> that providing such a type is higher-level than the Network.Socket
> library, since everything else is pretty much as unforgiving as C.

There's already extensive use of ADTs where C's socket interface accepts 
ints and pointers to untyped structs (e.g. struct sockaddr).

	<b