权限代码优化

由于在项目中需要两个左边的nav菜单，原先代码中的菜单权限控制只有两层，我优化了代码让路由可以无限嵌套给菜单使用
iview-admin/src/store/modules/app.js
>let accessCode = parseInt(Cookies.get('access'));
>state.menuList = Util.filterUnaccess(appRouter,accessCode);

/src/libs/util.js
>util.filterUnaccess=function (arr,currentAccess){
> let arrout=[];
> for (let index=0;index if (arr[index].children!=undefined&&arr[index].children.length!=0){
> arr[index].children=this.filterUnaccess(arr[index].children,currentAccess);
> }
> if (arr[index].access===undefined||this.showThisRoute(arr[index].access,currentAccess)){
> arrout.push(arr[index]);
> }
> }
> return arrout;
>}

Start with iview-admin/src/store/modules/app.js and /src/libs/util.js, reading how menuList is built and how filterUnaccess and showThisRoute currently handle route access. Verify the behavior with nested appRouter entries and confirm that menus can be nested beyond two levels while inaccessible routes remain filtered.

Written by the indexing model from the issue text.