Current insider builds of Windows have support for mounting individual
named pipe servers from the host to the guest. This allows, for example,
exposing the docker engine's named pipe to a container.
This change allows the user to request such a mount via the normal bind
mount syntax in the CLI:
docker run -v \\.\pipe\docker_engine:\\.\pipe\docker_engine <args>
Signed-off-by: John Starks <jostarks@microsoft.com>
