增加response的事件机制；为login增加事件；发布新版本

app/common/event/AdminLoginIndex/Index.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace app\common\event\AdminLoginIndex;
+
+class Index
+{
+    public function handle($params)
+    {
+        $controller = $params['controller'];
+
+        $controller->assign('captcha',1);
+
+        return [
+            'response' => $controller->fetch('login/ext/index'),
+        ];
+    }
+}