Optionally accept a Less func to implement sort.Interface

[phelmkamp]

Something like:

type personsLesser struct {
	Persons
	less func(i, j Person) bool
}

func (pl personsLesser) Less(i, j int) bool {
	return pl.less(pl.Ps[i], pl.Ps[j])
}

// Sort is a convenience method.
func (p Persons) Sort(less func(i, j Person) bool) {
	sort.Sort(personsLesser{
		Persons: p,
		less:    less,
	})
}

[phelmkamp]

Done