This adds a new libmachine API implementation that skips RPC and instead
uses a vendored in driver directly. This removes the need to download a
separate driver binary. Currently, only the "core" drivers, and kvm are
supported as vendored in. This means that xhyve is the only driver that
requires a separate binary for now.
Libmachine logs can be enabled with --v=3 or higher. --v=7 turns on
debug level info. This will simplify the debugging control plane and
allow us to transition off of libmachine logs in the future.
Matt Rickard
vishah