Update screenshots for "new" UI

[lfaraone]

@allenrabinovich updated the Zulip UI in February 2014. However, we never updated the screenshots on /hello to match.

It'd be nice to move away from images entirely and just embed the Zulip CSS, but I don't know if our CSS is sufficiently modular for that. So for this task, simply take new screenshots (preferably with the same copy) and cut a PR.

[brainwane]

(This would be easier with #1525.)

[lfaraone]

@timabbott is this worth doing yet, or is more work expected on @brockwhittaker 's branch?

[timabbott]

I think not; we may be getting rid of most of the screenshots anyway.

[zulipbot]

Hello @lfaraone, you have been unassigned from this issue because you have not updated this issue or any referenced pull requests for over 10 days.

You can reclaim this issue or claim any other issue by commenting @zulipbot claim on that issue.

Thanks for your contributions, and hope to see you again soon!

[timabbott]

This is done now.