Merge network-bytestring into network

[bos]

Now that we're actively maintaining the network package, I don't think there's any longer a good reason that we should continue to have a separate network-bytestring package.

[tibbe]

I agree. We can create a library proposal to merge the two. I also like to see a Network.Socket.Buffer that has functions such as:

recvInto :: Socket
         -> Ptr Word8
         -> Int
         -> IO Int

For the cases when you really want to reuse a buffer. We can then implement recv in terms of recvInto.