无限子分类

/**
 * 无限分类
 * @author lje lijunen.happy@163.com
 * 数据结构
 * $data = array（
            array（
                ‘id‘=>1
                ‘name‘=>‘开发语言‘
                ‘parent_id‘=>0
                ‘path‘=>0
            ）
            array（
                ‘id‘=>2
                ‘name‘=>‘java‘
                ‘parent_id‘=>1
                ‘path‘=>‘0-1‘
            ）
            array（
                ‘id‘=>4
                ‘name‘=>‘java jsp‘
                ‘parent_id‘=>2
                ‘path‘=>‘0-1-2‘
            ）
            array（
                ‘id‘=>6
                ‘name‘=>‘servet‘
                ‘parent_id‘=>4
                ‘path‘=>‘0-1-2-4‘
            ）
            array（
                ‘id‘=>5
                ‘name‘=