fix(message-timestamps): avoid duplicate timestamps
fix(message-timestamps): avoid duplicate timestamps

F5 on the messages page will lead to duplicating the message times. Probably because `document.arrive` catches initial nodes.

Let's avoid this by checking that there's no time inserted already.

Closes #47.

vk-x/vk-x,lucky-ly/vk-x,vk-x/vk-x,lucky-ly/vk-x