Version 2.8.0.0

* Breaking change: PortNumber originally contained Word32 in network

  byte order and used "deriving Ord". This results in strange behavior

  on the Ord instance. Now PortNumber holds Word32 in host byte order.

  [#347](https://github.com/haskell/network/pull/347)

* Breaking change: stopping the export of the PortNum constructor in

  PortNumber.

* Use bytestring == 0.10.* only.

* Use base >= 4.7 && < 5.