feat: 增加首頁評論數顯示

fix: 修復點擊toc後，滾動完toc的highlight在點擊的上一個元素
fix: 修復打賞按鈕Hover的bug close #473
improvement: 友情鏈接界面增加title顯示（top_img設為false時）
improvement: 優化toc顯示，當向上滾動時，導航欄不會遮擋 toc close #472
improvement: 升級facebook comment sdk版本

layout/includes/third-party/card-post-count/index.pug

@@ -0,0 +1,12 @@
+case theme.comments.use[0]
+  when 'Twikoo'
+    include ./twikoo.pug
+  when 'Disqus'
+  when 'Disqusjs'
+    include ./disqus.pug
+  when 'Valine'
+    include ./valine.pug
+  when 'Waline'
+    include ./waline.pug
+  when 'Facebook Comments'
+    include ./fb.pug