scan.go
func (s Scan) ToString() (out string) {
	for _, host := range s.Hosts {
		out += fmt.Sprintf("%s\n", host.ToString())
	}
	return
}
func (s Scan) ToString() (out string) {
	for _, host := range s.Hosts {
		out += fmt.Sprintf("%s\n", host.ToString())
	}
	return
}
// ToString returns the list of hosts into a pretty-printed format