display mail in iframe, add design for thread and unseen

back/mails/imap/Box.js

@@ -25,7 +25,6 @@ class Box {
     sync(savedUid, currentUid) {
         const promises = [];
         const mails = [];
-        console.log(savedUid, currentUid);
         const f = this.imap.seq.fetch(`${savedUid}:${currentUid}`, {
             size: true,
             envelope: true,