升级getEachProxy，处理proxy[param]为vm的情况。升级recycleEachProxy方法，回收subscribers。

```javascript
<!DOCTYPE html>
<html>
    <head>
        <title></title>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <script src="../avalon.js"></script>
    </head>
   <body class="ms-controller" 
         ms-controller="demo">
    <ul>
        <li ms-repeat="arr" 
            ms-click="$remove">{{el.a}}</li>
    </ul>
    <button ms-click="add">add</button>
    <script> 
        var demoVM = avalon.define('demo',function(vm){

            vm.arr = [{
                a:1
            }, {
                a:2
            }, {
                a:3
            }]

            vm.add = function() {
                demoVM.arr.push({
                    a: Math.random()
                });
            };
        });

    </script>
</body>
</html>
```

以上代码在IE6-8下按照如下操作顺序报错：

点击li，点击button