prawnsalad/KiwiIRC — pull request #629 by ehues (2014-11-29 22:49:58+00:00)
Title: Tell the user which messages arrived since they last saw the browser tab

When the user switches context away from our browser tab, draw a line under
the last seen message, so when they return they know which messages are new.

(do-over of https://github.com/prawnsalad/KiwiIRC/pull/625)