1.将class定义方式修改为interface定义,方面未来扩展

2.补全失的导入导出类型

types/cell.d.ts

@@ -2,9 +2,9 @@
 // Project: https://github.com/iview/iview
 // Definitions by: yangdan
 // Definitions: https://github.com/yangdan8/iview.git
-import Vue,{ VNode } from 'vue';
+import Vue, { VNode } from 'vue';
 
-export declare class Cell extends Vue {
+export declare interface Cell extends Vue {
   /**
    * 用来标识这一项
    */
@@ -72,7 +72,7 @@ export declare class Cell extends Vue {
   }
 }
 
-export declare class CellGroup extends Vue {
+export declare interface CellGroup extends Vue {
   /**
    * 点击单元格时触发
    *