- Move HyperKit code into a separate file. It should be compilable
on all supported OSes now.
- Add a (optional) subcommand to "moby run" to select a backend
i.e., "moby run hyperkit [options] [prefix]"
- On macOS the default is "hyperkit" so that:
"moby run [options] [prefix]"
just works
- Add enough command line parsing to make it easy to add new
backends to the run command
Update help messages.
Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>