optimize router && add Wechat api

system/lib/extra/wechat/handler/wechat.js

@@ -2,7 +2,7 @@
 module.exports = {
     checkSignature:function(){
         let signature = this.GET['signature'],
-            timestamp = this.GET['signtimestampature'],
+            timestamp = this.GET['timestamp'],
             nonce     = this.GET['nonce'],
             echostr   = this.GET['echostr'];
         if(signature && timestamp && nonce && echostr){