新特性：支持单据的1级转2级分录并汇总

使用说明：

一级分录转1、2级分录

对分录entrys（List）遍历，将源单的物料明细转成1/2级分录

取数脚本：

src.purinvoicesentry = src.entrys.group(material).entries() =>{

  material : key, //物料

  taxamount : value.sum(N amount), //合计

  purinvoicesdetail : value => {

    cmaterial : material, // 物料

    cextaxprice : unitPrice, // 不含税单价

    ctaxrate : taxRate, // 税率

    ctaxprice : taxPrice, // 含税单价

    camountax : taxAmount, // 税额

    invociceqty : quantity, // 发票数量

    cextaxamount : N amount - N taxAmount, // 不含税金额

    ctaxamount : amount, // 含税金额

    id : id // 分录ID

  }

};

二级分录转1级分录

反之，对二级分录进行降级，如对物料cmaterial分组，求和，统计，降为一级分录src.entrys

var src = {

         "taxsum":126.55,

         "supplyinvoiceno":"1",

         "purinvoicesentry":[

                   {

                            "purinvoicesdetail":[

                                     {

                                               "cmaterial":490292061493338112,

                                               "ctaxprice":110.0000000000,

                                               "ctaxamount":1100.00,

                                               "invociceqty":10.0000000000,

                                               "ctaxrate":0.1300000000,

                                               "cextaxamount":973.45,

                                               "id":800473768635276289,

                                               "cextaxprice":97.3451327434,

                                               "camountax":126.55,

                                               "$id":800473768635276289,

                                               "$pk":"id"

                                     },

              {

                                               "cmaterial":122324324,

                                               "ctaxprice":110.0000000000,

                                               "ctaxamount":1100.00,

                                               "in