[tz] [PROPOSED PATCH] Add xkcd

[Steve Summit]

Paul Eggert wrote:
> +The webcomic <em>xkcd</em> has the strip
> +"<a href='https://xkcd.com/673/'>The Sun</a>" (2009-12-09) and the panels
> +"<a href='https://xkcd.com/1017/'>Backward in Time</a>" (2012-02-14),
> +"<a href='https://xkcd.com/1061/'>EST</a>" (2012-05-28), and
> +"<a href='https://xkcd.com/1335/'>Now</a>" (2014-02-26).

The same author's "What If" series was also relevant at #26
(especially given the events of last November):

http://what-if.xkcd.com/26/

Not specifically related to time zones, but those interested in
date and time notations will also want to keep this one handy,
if for no other reason than to use as the occasional cluebat:
https://xkcd.com/1179/