Show embedded comments although page body is .dw-dummy.
Specify server origin when logging in, so works in <iframe>.
Add comments toolbar, with comment count and login/logout button

Change from CSS ids to classes, so can have many login/out buttons (in
comments toolbar and in page top bar).

Also change from "Log in"/"Log out" to "Login"/"Logout", that's more
common.
Specify server origin for all '/-/...' URLs

Otherwise the <iframe>'s parent's origin is used.
Change ?page-info to /-/load-my-page-activity and specify server origin.
Make embedded replies work: allow replies to comment id 0.
Show embedded comments: use page root = None

Also change some `List`s to `Seq`s.
Fix comment count bug.
Show comments toolbar also for embedded comments.
Avoid underlining "buttons" by changing some <a> to <span>

Changing to <button> sometimes clashes with jQuery UI styles, and
sometimes results in the wrong width.
Make the rate button work in an <iframe>

- Post JSON, not HTML, to `d.i.serverOrigin/-/rate`, not `?rate`
- Reply with JSON, use the BrowserPagePatcher
Fix my-rating-tags bug: let new ratings overwrite old

Otherwise "you rated it: ..." text won't change, even if the user changes
his/her ratings.
Make the Report button work in embedded discussions

- JSON-post to `d.i.serverOrigin/-/flag`, don't send form-data
  to `?flag`.
- Patch page with reply
Remove pointless <form> attributes

Not needed when posting JSON instead.
Fix bug: Don't require that OpenID/OpenAuth login button be an <a>.
Make improvements work in <iframe>

Get and post from/to `d.i.serverOrigin/-/improvements` and `/-/improve`,
don't use ?viewedits and ?applyedits.
Remove `d.i.mergeChangesIntoPage`, it was buggy and is no longer used.
Fix iframe <--> parent window serious typo bugs

The bug had no effect in Chrome, surprisingly.
Hide <iframe> border, 'seamless' doesn't work in FireFox.
Work around FireFox mouseup-event-lost issue related to <iframe>.