json api: Add body_html attribute.

Same format as for standard things.
Add RSS views of liveupdate events.
Prevent timetext reflow jitter with fixed-width time column.

As the timestamps, especially the first one with its larger text, update
the time column would jump around in size.  This was very jarring and
annoying. This fixes that reflow by making the time column fixed size.

The max-width is necessary in addition to width because browsers will
auto-grow the table column without it.
Hide the welcome bar in embeds.
Limit the number of reporters shown on main page.
Change a few publicly visible "editors" to "reporters".

This is a partial fix, the backend will need some cleanup and migration
as well.  I think "reporter" is the word we'll go with.
Fix final row messing up narrow screen mode.

The timestamp wasn't affected by the styling so it caused everything to
cramp down into the 150px allocated to the default timestamp column.
Open up reporter list management to other reporters.