feat: 美化 firefox 瀏覽器滾動條

fix: Utterances 評論區在多個頁面顯示的是同一個評論區
fix: 修復評論配置爲 Livere 和 Facebook Comments 時，最新評論模塊仍然顯示的 bug
improvement: blueimp_md5 CDN 可配置
improvement: timeline 優化
improvement: css優化
improvement: 友情鏈接優化

package.json

@@ -1,6 +1,6 @@
 {
   "name": "hexo-theme-butterfly",
-  "version": "4.0.0-b11",
+  "version": "4.0.0",
   "description": "A Simple and Card UI Design theme for Hexo",
   "main": "package.json",
   "scripts": {