add set method for request

src/Request/Http.php

@@ -219,6 +219,16 @@ final class Http extends Request
     }
 
     /**
+     * set to params
+     *
+     * @param string $key 关键字
+     * @param mix $val 值
+     * @return void
+     */
+    public function set($key, $val) {
+        $this->params[$key] = $val;
+    }
+    /**
      * isXmlHttpRequest
      *
      * @param void