Add listings of live/closed events for admins to see and some minor visual cleanups.

* 62d13e9 fixes the reddit header etc. being visible in embeds.
* c17375a is pretty self explanatory
* ff542bb does the 1000px centering for all liveupdate-related pages and then brings the tabs contributors see in to match as well.
* bd0abbc is part of my ongoing campaign to make the actual stream of updates page be called the "app" so i can free up "event" for use in the listings etc.
* 8dc8253 does some cached query and listing stuff to get us a web-visible view of the world of liveupdates

:eyeglasses: @umbrae @powerlanguage @bsimpson63