libmachine/mcnutils/b2d.go
func (b *B2dUtils) DownloadISO(dir, file, isoURL string) error {
	log.Infof("Downloading %s from %s...", b.path(), isoURL)
	return b.download(dir, file, isoURL)
}
func (b *B2dUtils) DownloadISO(dir, file, isoURL string) error {
	log.Infof("Downloading %s from %s...", b.path(), isoURL)
	return b.download(dir, file, isoURL)
}
// DownloadISO downloads boot2docker ISO image for the given tag and save it at dest.