Update inmem pipe to use go channel
Update inmem pipe to use go channel

The inmemory pipe implementation may simply use go channels instead of using a pipe.

Closes #92

Signed-off-by: Derek McGowan <e1c79a582b6629e6b39e9679f4bb964d25db4aa8@mcgstyle.net> (github: dmcgowan)

docker/libchan