radiogroup.go
func (c *RadioGroup) AddItem(r *Radio) {
	c.items = append(c.items, r)
	r.SetGroup(c)
}
func (c *RadioGroup) AddItem(r *Radio) {
	c.items = append(c.items, r)
	r.SetGroup(c)
}
func ( c * RadioGroup ) AddItem ( r * Radio ) { c . items = append ( c . items , r ) r . SetGroup ( c ) }
// AddItem add a new radio button to group
AddItem add a new radio button to group