[CH-3] Added named pipe backend

[qnikst]

[Imported from JIRA. Reported by Ryan Newton @rrnewton) as CH-3 on 2012-02-21 05:21:03]
Taken from: https://cloud-haskell.atlassian.net/browse/CH-3

This has some limitations remaining (message size) but works for all of the demos in DemoTransport.