Set up Zeroconf locally.

OS X will resolve .local domains automatically. We should also
be able to make this work on Linux and Windows.

See: #240 

TODO:

* [ ] Make subdomains resolve properly.
* [ ] Test on Linux/Ubuntu.
* [ ] Test on Windows.
* [ ] Switch to subdomains instead of subdirectories.
* [ ] Refactor vip-init script to only work when `--server` is set.