Use Windows named pipe

[StefanScherer]

I've tested Visualizer with Windows Server Insider 16278 and Docker 17.09.0-ce-rc2 which allows me to map the Windows named pipe \\.\pipe\docker_engine into a Windows container.
This is the equivalent to the Unix socket /var/run/docker.sock.

This PR adds the usage of the Windows named pipe if running on Windows.

My Dockerfile.insider to build the example image stefanscherer/visualizer-windows:insider that is also available on Docker Hub:

FROM stefanscherer/node-windows:8.4.0-insider

WORKDIR /app

# Only run npm install if these files change.
ADD ./package.json /app/package.json

# Install dependencies
RUN npm install --unsafe-perm=true

# Add the rest of the sources
ADD . /app

USER ContainerAdministrator
# Build the app
RUN npm run dist

# Number of milliseconds between polling requests. Default is 200.
ENV MS 200

EXPOSE 8080

CMD ["npm.cmd","start"]

After building the image and running it

docker run -v //./pipe/docker_engine://./pipe/docker_engine -d -p 8080:8080 stefanscherer/visualizer-windows:insider

The Visualizer is running and can monitor the services in the swarm. Only from time to time there are some connection problems to that named pipe. Here is a screenshot with some debug console.logs that shows that the most of the requests are successful.

This problem may be related to microsoft/go-winio#67 which we found running Portainer with a Windows named pipe in a Windows container. So this is no problem of the Visualizer itself.

/cc @friism