保存关注到本地，时间线分子模式

src/Attention.js

@@ -0,0 +1,7 @@
+export function load_attentions() {
+  window.saved_attentions = JSON.parse(localStorage['saved_attentions'] || '[]');
+}
+
+export function save_attentions() {
+  localStorage['saved_attentions'] = JSON.stringify(window.saved_attentions);
+}