Say number of hours till next meeting when notifying

[edunham]

While the absolute time of the meeting is sufficient, I find that I spend a couple minutes looking up what the UTC time is for my local time zone whenever Meetingbot notifies.

Instead of making me smarter by hoping I memorize UTC, could we make the robot smarter by having it say "Next meeting is at ___ UTC, that's ___ hours from now" instead?